Chapter IV · (continued 5)

The practice of re-vaccination was usual on the Continent long before the English took to it. The reason of this was that a second inoculation of cowpox was not resorted to for the greater security of infants and young children, who were then the principal victims of smallpox in this country, but for the protection of adults, who made a great part of the subjects of the epidemics in other countries. There were so many adult deaths in the great Paris epidemic of 1825 that the news of it reads like the English references to smallpox in the time of the Stuarts. We obtain exact statistics of the ages in the 3323 fatal cases of smallpox in Paris from 1842 to 1851. Reduced to percentages they were as follows:

All ages 0-5 5-10 10-20 20-30 30-40 Over 40

100 33·8 5·9 13·25 32·95 10·95 3·15

Two-thirds of the deaths were above the age of five years, an age-incidence that was not reached in London until a whole generation after. The contrast with British experience comes out in concrete form in the following table of the age-incidence of 342 fatal attacks of smallpox in 1850 and 364 in 1851, in Paris (pop. 1,000,000), and of 584 fatal attacks in Glasgow in the single year 1852 (pop. 370,000)[1170]:

Age-incidence of fatal Smallpox in Paris and in Glasgow.

Paris, 1850-51 (706 deaths) Glasgow, 1852 (584 deaths)

Under one year 126 188

One to two 32 150

Two to five 94 189

Five to ten 31 20

Ten to fifteen 20 4

Fifteen to twenty 51 2

Twenty to twenty-five 109 19

Twenty-five to thirty 89 2

Thirty to forty 128 8

Forty to fifty 22 1

Over fifty 4 1

In other parts of the Continent of Europe the frequency of smallpox in adults was not less remarked than in France in the second quarter of the 19th century. English writers had been able at one time to point to foreign countries for the success of infantile vaccination. Sweden and Denmark were for a long time classical illustrations; then it was Germany’s turn. “In Berlin during 1821 and 1822,” said Roberton, “only one died of smallpox in each year. In the German States, vaccination has become universal, and in them as well as in various other countries the smallpox is almost unknown.” When we next find German experience appealed to, it is to enforce the need of re-vaccination: “In 1829,” said Gregory, “the principal Governments of Germany took alarm at the rapid increase of smallpox, and resorted to re-vaccination as a means of checking it. In Prussia, 300,000 had been re-vaccinated, and the same number in Würtemberg. In Berlin nearly all the inhabitants had undergone re-vaccination[1171].” It was about the same time that a second vaccination became obligatory in the armies of Prussia, Würtemberg, Baden and other German States, and among the pupils of schools when they reached the age of twelve years. Dr Gregory, in his speech at the Medical and Chirurgical Society of London in December, 1838, urged the need of re-vaccination not only by the example of Germany, but also by the experience of Copenhagen, where a thousand cases of smallpox had been received into the hospital (it was nearly always adults that were taken to the general hospitals) in twenty-one months of 1833-34, nine hundred of them being of vaccinated persons[1172]. Gregory was in advance of his age in advocating re-vaccination for England. His own cases at the Smallpox Hospital of London were, it is true, nearly all adults, according to the rules of the charity. But they were not representative even of the smallpox of the capital; and in England at large smallpox in 1839 was still distinctively a malady of the first years of life. It was not until youths and adults began to have smallpox in large numbers in the epidemic of 1871-72 that the doctrine of re-vaccination was generally apprehended in England. Medical truth, like every other kind of truth except that of geometry, is conditioned by time and place. What was a truth to the Germans in 1829 was not a truth to us until some forty years after. Dr Gregory, Sir Henry Holland and others advised re-vaccination after the epidemic of 1837-40; but as late as 1851 the National Vaccine Establishment denounced it as incorrect in theory and uncalled-for in practice.

After the great epidemic of 1837-40, there was an interval of a whole generation until smallpox broke out again on anything like the same scale, in 1871 and 1872. But it had risen to a considerable height at shorter intervals—in 1844-45, which were the years when vast numbers of navvies were employed making railroads all over England, in 1847 and successive years to 1852, which was the period of the great Irish migration after the potato-famine, in 1858, for which I find no explanation, and in the period from 1863 to 1865, which was again a time of somewhat high typhus mortality, not only in the Lancashire cotton-districts but also in London. The great epidemic of 1871 and 1872 finds no better explanation than our neighbourhood to Germany and Belgium, where the mortality from smallpox was far greater than in Britain, and was doubtless favoured by the state of war in 1870-71. The following tables for London, and for England and Wales in comparison with measles, scarlatina and diphtheria, show the progress of smallpox from the epidemic of 1837-40 to the present time:

Smallpox Deaths in London from the beginning of Registration.

Year Deaths

1837 (6 mo.) 763

1838 3817

1839 634

1840 1235

1841 1053

1842 360

1843 438

1844 1804

1845 909

1846 257

1847 255

1848 1620

1849 521

1850 499

1851 1062

1852 1150

1853 211

1854 694

1855 1039

1856 531

1857 156

1858 242

1859 1158

1860 898

1861 217

1862 366

1863 1996

1864 547

1865 640

1866 1391

1867 1345

1868 597

1869 275

1870 973

1871 7912

1872 1786

1873 113

1874 57

1875 46

1876 736

1877 2551

1878 1417

1879 450

1880 471

1882 430

1883 146

1884 898

1885 914

1886 5

1887 7

1888 5

1889 0

1890 3

1891 1

1892 11

1893 206

England and Wales: Deaths by Smallpox, Measles, Scarlatina and Diphtheria from the beginning of Registration.

Smallpox Measles Scarlet Fever Diphtheria

1837 (½) 5811 4732 2550 —

1838 16268 6514 5862 —

1839 9131 10937 10325 —

1840 10434 9326 19816 —

1841 6368 6894 14161 —

1842 2715 8742 12807 —

1847 4227 8690 14697 —

1848 6903 6867 20501 —

1849 4644 5458 13123 —

1850 4665 7082 13371 —

1851 6997 9370 13634 —

1852 7320 5846 18887 —

1853 3151 4895 15699 —

1854 2868 9277 18528 —

1855 2523 7354 16929 385

1856 2277 7124 13557 603

1857 3236 5969 12646 1583

1858 6460 9271 23711 6606

1859 3848 9548 19310 10184

1860 2749 9557 9681 5212

1861 1320 9055 9077 4517

1862 1638 9860 14834 4903

1863 5964 11340 30473 6507

1864 7684 8322 29700 5464

1865 6411 8562 7700 4145

1866 3029 10940 11683 3000

1867 2513 6588 12380 2600

1868 2052 11630 21912 3013

1869 1565 10309 27641 2606

1870 2620 7543 32543 2699

1871 23062 9293 18567 2525

1872 19022 8530 11922 2152

1873 2308 7403 13144 2531

1874 2084 12235 24922 3560

1875 849 6173 20469 3415

1876 2468 9971 16893 3151

1877 4278 9045 14456 2731

1878 1856 9765 18842 3498

1879 536 9185 17613 3053

1880 648 12328 17404 2810

1881 3698 7300 14275 3153

1882 1317 12711 13732 3992

1883 957 9329 12645 4218

1884 2216 11324 11143 5020

1885 2827 14495 6355 4471

1886 275 12013 5986 4098

1887 506 16765 7859 4443

1888 1026[1173] 9784 6378 4815

1889 23 14732 6698 5368

1890 16 12614 6974 5150

1891 49 12673 4959 5036

1892 431 13553 5618 6552

1893 1455 10764 6869 8918

The great epidemic of 1837-40 was the last in England which showed smallpox in its old colours. The disease returned once more as a great epidemic in 1871-72, after an interval of a whole generation (in which there had been, of course, a good deal of smallpox); but the epidemic of 1871-72 was different in several important respects from that of 1837-40. It was a more sudden explosion, destroying about the same number in two years (in a population increased between a third and a half) that the epidemic a generation earlier did in four years. It was an epidemic of the towns and the industrial counties, more than of the villages and the agricultural counties; it was an epidemic of London more than of the provinces; and it was an epidemic of young persons and adults more than of infants and children. The great epidemic of 1871-72 brought out clearly for the first time all those changes in the incidence of smallpox; but things had been moving slowly that way in the whole generation between 1840 and 1871. Experience subsequent to 1871-72 has shown the same tendency at work.

To begin with the changed incidence upon rural and urban populations, a glance down the following Table, will show that the counties marked *, with a smaller share in 1871-72, in a total of deaths in all England and Wales which was nearly the same as in the great epidemic a generation before, are nearly all those with a population more purely rural[1174]:

Incidence of the Smallpox Epidemics of 1837-40 (four years) and 1871-72 (two years) respectively upon the Counties of England and Wales.

1837-40 1871-72

England and Wales 41,253 42,084

Metropolis 6421 9698

* Surrey (extra-metr.) 383 231

* Kent (extra-metr.) 817 537

* Sussex 161 126

Hampshire 348 1103

* Berkshire 450 46

* Middlesex (extra-metr.) 418 306

* Hertfordshire 260 157

* Buckinghamshire 268 53

* Oxfordshire 199 109

Northamptonshire 399 563

* Huntingdonshire 65 14

Bedfordshire 125 128

* Cambridgeshire 400 175

* Essex 773 583

* Suffolk 506 348

* Norfolk 1038 895

* Wiltshire 548 85

* Dorsetshire 329 163

* Devonshire 1097 838

* Cornwall 767 531

* Somersetshire 1466 412

* Gloucestershire 1072 323

* Herefordshire 191 34

* Shropshire 345 161

* Worcestershire 1002 529

Staffordshire 1328 3050

* Warwickshire 957 785

Leicestershire 528 622

Rutlandshire 8 7

Lincolnshire 482 498

Nottinghamshire 562 983

* Derbyshire 329 297

* Cheshire 1141 310

† Lancashire 7105 4151

† Yorkshire W. Riding 2858 2609

"E. Riding 480 452

"N. Riding 236 405

Durham 798 4767

Northumberland 569 1512

* Cumberland 549 366

* Westmoreland 98 41

Monmouthshire 672 904

* Wales 2699 2314

The counties which were most lightly visited in 1871-72, as compared with 1837-40, were the agricultural and pastoral. In the outbreaks subsequent to 1871-72, smallpox has almost ceased to be a rural infection in Scotland and Ireland as well as in England. The great change that has come over it in that respect is shown in the following table, in which the annual death-rates from smallpox per 100,000 living are contrasted, for children under five, in each of several agricultural counties, with the mean of all England and of London, 1871-80, and with the corresponding scarlatinal death-rates in the right-hand column:

Annual Death-rates of Children under five, per 100,000 living, 1871-80.

Smallpox Scarlatina

All England 53 349

London 113 307

Sussex 9 100

Berkshire 4 141

Bucks 4 160

Oxfordshire 9 167

Huntingdonshire 3 205

Bedfordshire 11 242

Cambridgeshire 18 112

Suffolk 12 136

Wiltshire 5 210

Dorsetshire 15 152

Herefordshire 5 166

Shropshire 12 247

But the history of smallpox since the great epidemic of 1871-72 has brought out still another tendency in the same direction, namely, the increasing share of London in the whole smallpox of England. In the epidemic of 1837-40, which reached to almost every parish of England and Wales, London had 6449 deaths in a total of 41,644, or between a sixth and a seventh part, having rather less than an eighth part of the population. In the epidemic of 1871-72, London had between a fourth and a fifth part of the deaths (9698 in a total of 42,084), having then about a seventh part of the population. In 1877, more than half of all the smallpox deaths were in London, and in the year after as many as 1417 in a total of 1856. In 1881, London had about two-thirds of the deaths from smallpox in all England and Wales; but in the epidemic of 1884-85, it had only over a third part (1812 in a total of 5043). This excess of London’s share over that of the provinces is expressed in the following table, showing the respective rates of smallpox mortality per million of the population:

Smallpox Deaths in London and the Provinces, per million of population.

1847-9 1850-4 1855-9 1860-4 1865-9 1870-4 1875-9 1880-4

London 460 300 237 281 276 654 292 244

Provinces 274 271 192 175 172 339 48 34

If the table were continued to the very latest date, it would show the provinces recovering their share, but upon a slight prevalence of the epidemic as a whole, the deaths in London having been mere units from 1886 to 1892, while in 1888 there was a severe epidemic in Sheffield and in 1892-93 a good deal of the disease in a few manufacturing towns of the North-western and Midland divisions. It would be a not incorrect summary of the incidence of smallpox in Britain to say, that it first left the richer classes, then it left the villages, then it left the provincial towns to centre itself in the capital; at the same time it was leaving the age of infancy and childhood. Of course it did none of these things absolutely; but the movement in any one of those directions has been as obvious as in any other. Measles and scarlatina have not shown the same tendency to change or limit their incidence. Smallpox may have surprises in store for us; but, as it is an exotic infection, its peculiar behaviour may not unreasonably be taken to mean that it is dying out,—dying, as in the death of some individuals, gradually from the extremities to the heart.

With all those changes, the fatality of smallpox, or the proportion of deaths to attacks, came out in the great epidemic of 1871-72 curiously near that of the 18th century epidemics, namely, one death in about six cases. This rate comes from the hospitals of the Metropolitan Asylums Board according to the following table:

Admissions for Smallpox, with the Deaths, at the hospitals of the Metropolitan Asylums Board, from the opening of the several hospitals to 30 April, 1872.

Males Females Both Sexes

Age-periods Adm. Died Percentage of deaths Adm. Died Percentage of deaths Adm. Died Percentage of deaths

Under 5 434 235 54·15 469 236 50·32 903 471 52·15

5-10 851 236 27·73 821 196 23·87 1672 432 25·83

10-20 2827 265 9·37 2513 237 9·43 5340 502 9·40

20-30 2561 465 18·15 1922 285 14·82 4483 750 16·72

30-40 939 244 26·00 665 136 20·45 1604 380 23·69

40-50 316 100 31·64 242 64 26·45 558 164 29·39

50-60 85 18 21·17 88 31 35·22 173 49 28·32

Above 60 40 8 20·00 35 7 20·00 75 15 20·00

8053 1571 19·49 6755 1192 17·64 14,803 2763 18·65

These admissions to hospitals included attacks of every degree of severity, the intention of the hospitals being to isolate all cases, mild and severe alike; so that, although these are technically hospital cases, they are not comparable to the select class admitted to the old Smallpox Hospital of London, but to the cases of smallpox in former times in the community at large. Although the general average of deaths in 14,808 cases, namely, 18·65 per cent., is nearly the same as (being slightly higher than) that of the equally comprehensive totals of 18th century cases given at p. 518, yet the average is made up in a different way. In some of the 18th century epidemics, such as that of Chester in 1774, all the deaths were under ten years of age, and yet the average rate of fatality was only 14 or 15 per cent. The much higher rate of fatality from birth to five years and from five years to ten in the London epidemic of 1871-72 (which is confirmed in part by the Berlin statistics of the same years), must have had some special reasons. One reason, doubtless, was that the attack of smallpox in recent times has fallen upon comparatively few children, whereas in former times it fell upon nearly the whole; and it may be inferred that the infants who have been in recent times subject to the attack of smallpox have also been of the class that are most likely to die of it. The high rates of fatality at the ages above thirty in the table agree with the experience of all times.

The percentages of fatalities from smallpox in the hospitals of the Metropolitan Asylums Board have varied as follows from their opening to the present time:

Cases Percentage of deaths

1 Dec. 1870-3 Feb. 1871 582 20·81

4 Feb. 1871-31 Jan. 1872 13,145 18·95

1872-3 2362 17·84

1873-4 191 } } 17·02

1874 (11 mo.) 120

1875 111

1876 2150 21·64

1877 6620 17·92

1878 4654 17·99

1879 1688 15·69

1880 2032 15·95

1881 8671 16·61

1882 1854 12·96

1883 626 16·06

1884 6567 15·98

1885 6344 15·8

1886 132 } } } } 14·28

1887 59

1888 67

1889 5

1890 27

1891 64

1892 348 11·29

1893 2376 7·75

The decline in average fatality in the last two years is remarkable, and is to be explained chiefly by the mild type of smallpox which has been prevalent; a very small fraction of the patients attacked between the ages of ten and twenty-five have died; and these are some two-fifths of the whole. This is shown in the following age-table of 2374 cases admitted to the Metropolitan Board Hospitals in 1893:

Smallpox in London, 1893.

Age-period Cases Deaths %

0-5 168 53 31·5

5-10 191 16 8·3

10-15 230 7 3·0

15-20 340 7 2·0

20-25 393 13 3·3

25-30 298 23 7·7

30-35 250 14 5·6

35-40 182 13 7·1

40-50 199 18 9·0

50-60 79 9 11·4

60-70 35 6 17·1

70-80 9 1 11·1

The low rate of fatality during the slight epidemic revival of smallpox in 1892-93 has been found to obtain wherever the disease has occurred:

Smallpox in the Provinces, 1892-93.

Cases Deaths Fatalities per cent.

Birmingham 1203 96 8

Warrington 598 60 10

Halifax 513 44 8·5

Manchester 406 27 6·7

Glasgow 279 23 8·2

Liverpool 194 15 7·7

Brighouse 134 15 11·2

Aston Manor 113 6 5·3

Leicester 362 21 5·8

St Albans 58 6 10·4

3860 313 8·10

The ages under ten years had only 290 in 3644 of these cases; but those 290 cases had 70 in 302 of the deaths.

In the comparative table for Ireland, of deaths by smallpox, measles, scarlatina and diphtheria, measles in a decreasing population has changed little, while scarlatina has declined greatly, and smallpox has fallen during the last ten years almost to extinction.

Ireland: Deaths by Smallpox, Measles, Scarlatina and Diphtheria from the beginning of Registration.

Smallpox Measles Scarlatina Diphtheria

1864 854 630 2605 661

1865 461 1036 3683 480

1866 194 851 3501 317

1867 21 1292 2145 189

1868 23 1251 2696 202

1869 20 948 2670 243

1870 32 954 2978 188

1871 665 547 2707 226

1872 3248 1380 2459 257

1873 504 1303 2092 326

1874 569 667 4034 565

1875 535 898 3845 443

1876 24 664 2112 368

1877 71 1562 1117 288

1878 873 2212 1079 296

1879 672 860 1688 320

1880 389 1025 1344 314

1881 72 402 1230 323

1882 129 1518 2443 385

1883 16 801 1765 239

1884 1 559 1377 354

1885 4 1323 1147 296

1886 2 284 850 336

1887 14 1307 973 381

1888 3 1935 849 447

1889 0 574 457 358

1890 0 726 319 346

1891 7 240 308 281

1892 0 1183 419 286

In the great Irish famine of 1846-49, comparatively little is heard of smallpox. It would appear to have been less diffused through the country than in former famines, such as that of 1817-18, or those of the first part of the 18th century, just in proportion as the vagrancy of famine-times was checked by the establishment of workhouses. In the workhouses and auxiliary workhouses during the ten years 1841-51, smallpox is credited with 5016 deaths, while measles has 8943, fever 34,644, dysentery 50,019, diarrhoea 20,507, and Asiatic cholera 6716. Registration began in Ireland in 1864, and showed little smallpox for the first few years. The next great epidemic, of 1871-72, showed the incidence upon the large towns, and the comparative immunity of the country population, even more strikingly than in England. In a total mortality of 3913 during the two years of 1871 and 1872, the three counties of Dublin, Cork and Antrim had the following enormous share, which fell mostly to the three cities of Dublin, Cork and Belfast:

Dublin Co. 1825

Cork Co. 1070

Antrim 510

3405 deaths in 3913 for all Ireland.

In that epidemic the whole province of Connaught had only 25 deaths from smallpox; but a subsequent visitation, a few years after, fell mainly upon Connaught.

The epidemic which began in Scotland in 1871 was distributed over a somewhat longer period than the corresponding outbreak in England; but the bulk of it fell in the two years 1871 and 1872. The total of 3890 deaths in those two years was distributed as follows:

Eight largest towns 2441

Next largest towns 259

Small town districts 574

Mainland rural districts 586

Insular rural districts 30

3890

Glasgow had a considerably smaller relative share than Edinburgh, and altogether a much lighter incidence of the disease than in the years 1835-52, for which the figures have been given above (pp. 600-1). In the following table of the annual deaths in Scotland from the beginning of registration, the four other infective diseases of childhood included along with smallpox show by comparison the remarkable decline of smallpox since 1874, scarlatina being the only other infection of childhood which has become greatly less common or less fatal.

Scotland. Deaths by Smallpox, Measles, Scarlatina, Diphtheria and Whooping-Cough, from the beginning of Registration.

Smallpox Measles Scarlatina Diphtheria Whooping-Cough

1855 1209 1180 2138 — 1903

1856 1306 1033 3011 — 2331

1857 845 1028 2235 76 1539

1858 332 1538 2671 294 1963

1859 682 975 3614 415 2660

1860 1495 1587 2927 480 1812

1861 766 971 1764 681 2204

1862 426 1404 1281 997 2799

1863 1646 2212 3413 1745 1649

1864 1741 1102 3411 1740 1993

1865 383 1195 2244 995 2318

1866 200 1038 2706 685 1860

1867 100 1341 2253 610 1728

1868 15 1149 3141 749 2490

1869 64 1670 4680 663 2461

1870 114 834 4356 630 1783

1871 1442 2057 2586 880 1504

1872 2448 925 2101 1045 2850

1873 1126 1450 2227 1203 1598

1874 1246 1103 6321 1163 1690

1875 76 1022 4720 867 2431

1876 39 1241 2364 861 2250

1877 38 1019 1374 956 1571

1878 4 1372 1870 1033 2788

1879 8 769 1592 862 2483

1880 10 1427 2165 838 2641

1881 19 1012 1573 816 1620

1882 3 1289 1583 961 2108

1883 11 1629 1336 747 2968

1884 14 1440 1266 830 2511

1885 39 1426 944 688 2157

1886 24 681 1058 583 1882

1887 17 1598 1179 805 3212

1888 3 1406 732 872 1722

1889 8 1948 701 968 2268

1890 0 2509 739 1018 3039

1891 0 1775 736 830 2437

The age-incidence of Smallpox in various periods of history.

Among the various changes of incidence that have attended the recent decline of smallpox in England, Ireland and Scotland, there is one that calls for more extended notice, namely, the fact that the malady has in great part ceased to be an infection of infancy and childhood and has become more distinctively an infection of adolescence and mature age. In no period of its history has smallpox been so purely an infantile complaint as measles[1175], nor so purely a malady of childhood and early youth as scarlatina or diphtheria[1176]. When it first rose to prominence in England, from the reign of James I. onwards, it attacked adults in a large proportion; of which fact the evidence, although not statistical, is sufficient. But, as the disease became nearly universal and ubiquitous, it was so commonly passed in infancy or childhood, that few grew to maturity without having had it. The number of adult cases diminished in proportion as the disease became more nearly universal. In the great period of smallpox in the 18th century, about nine-tenths of the deaths occurred under the age of five, and nearly all the remaining fraction between five and ten years, at Manchester, Chester, Warrington, Carlisle and Kilmarnock. But in London there were always a good many adult deaths, the reason commonly given being that there was a steady influx to the capital of domestic servants and others from country parishes where the epidemics came at sufficiently long intervals to let many children grow up without incurring the risk of it. Also at Geneva and the Hague, in the 18th century, there were many more deaths above the age of five than in the English provincial towns at the same time.

Ages at Death from Smallpox at Geneva (including Measles) and at the Hague (Duvillard).

All ages 0-1 -2 -3 -4 -5 -6 -7 -8 -9 -10 -15 -20 -25 -30 -35 -40 -45

Geneva (1700-83) 3328 555 608 588 426 346 232 185 99 67 44 84 36 26 21 0 0 0

The Hague (15 years of 18th cent.) 1455 172 170 179 224 160 148 114 78 58 23 47 17 24 14 10 8 3

Twenty-four per cent. of the smallpox deaths in the 18th century at Geneva were above the age of five years, and at the Hague thirty-seven per cent., while in the former the ratio would probably have been higher but for the inclusion of measles. But, with this comparatively high ratio of deaths above the age of five, smallpox was a much less important cause of mortality at Geneva and the Hague than at Manchester, Glasgow, Chester, and most other provincial cities of this country, making about a fifteenth part of the deaths from all causes in the former, and as high as a sixth part in the latter.

The infantile character of smallpox was as marked as ever in the epidemic of 1817-19; of which the Norwich statistics are sufficient proof. As late as the epidemic of 1837-40, smallpox was still distinctively a malady of infants and young children in Britain, although that was by no means the case on the continent of Europe at the same time. The following was the age-incidence of fatal smallpox at Liverpool and Bath in the last six months of 1837.

At all ages Under 1 1-2 2-3 3-4 4-5 5-6 6-10 Above 10

Liverpool Deaths 495 143 127 77 64 24 19 20 25

Ratios per cent. 100 28·65 25·45 15·43 17·63 7·81 5·01

Bath Deaths 151 33 31 33 17 17 6 6 10

Ratios per cent. 100 21·56 20·26 21·56 22·2 7·84 6·53

In the third year of the epidemic, 1839, the ratio of deaths above the age of five was still less at Manchester, Liverpool and Birmingham, being only four and a half per cent. (26 in a total of 522). At Glasgow, from 1835 to 1839, twelve per cent. of the smallpox deaths were above the age of five (see p. 600). These are the rates of provincial cities; but in a total of 8714 deaths in the year 1839, added together from London and the provinces, about twenty-five per cent. were over five, and of these a moiety were over ten years:

All ages Under five Five to ten Above ten

8714 6453 1122 1139

A good deal of that mortality above the age of five must have come from London, according to the probability of the following table, which is of six years’ later date, but the nearest that can be got for London alone:

London, 1845. Ages at Death from Smallpox, Measles and Scarlatina.

Smallpox Measles Scarlatina

Total at all ages 909 2318 1085

Under One year 209 353 88

One to Two 133 832 167

Two to Three 91 511 181

Three to Four 81 272 183

Four to Five 63 153 115

Five to Ten 136 168 254

Ten to Fifteen 33 18 46

Fifteen to Twenty 34 3 14

Twenty to Twenty-five 54 1 8

Twenty-five to Thirty 38 2 6

Above Thirty 37 5 23

The ratio of smallpox deaths above five was 37·5 per cent., of measles deaths 8·4 per cent., and of scarlatina deaths 32·3 per cent. Measles and scarlatina have kept these ratios somewhat uniformly to the present time, but the ratio of smallpox deaths above the age of five has increased according to the following table for England and Wales from 1851 to 1890:

Period Percentage of smallpox deaths above five years Percentage of measles deaths above five years Percentage of scarlatina deaths above five years

1851-60 38 10 36

1861-70 46 8 36

1871-80 70 8 34

1881-90 77 8 36

The progressive raising of the age of fatal smallpox is shown in another way by taking the ratio of the deaths per million living at all ages and at each of eleven age-periods[1177]:

Smallpox Deaths per million living at each age-period.

Period All ages 0- 5- 10- 15- 20- 25- -35 -45 -55 -65 75 and over

1851-60 221 1034 257 73 93 130 92 53 38 24 18 14

1861-70 163 654 145 56 86 136 102 73 49 36 26 22

1871-80 236 527 284 137 197 300 239 168 111 71 46 35

It was the great epidemic of 1871-72 that brought out the change of age-incidence most concretely, just as it brought out, in contrast to the last great epidemic in 1837-40, the decline in the rural and the increase in the industrial centres. In the three years before the outburst of 1871 the deaths under five and over five were approaching an equality; in the epidemic itself the old ratios were suddenly reversed:

Year Smallpox deaths under five Smallpox deaths over five

1868 1234 818

1869 892 673

1870 1245 1375

1871 7770 15356

1872 5758 13336

In the whole generation between 1840 and 1871, in which there was no great and general epidemic of smallpox, many had passed from childhood to adolescence and maturity without encountering the risk of it. When the epidemic of 1871 began, it found many in youth or mature years who had not been through the smallpox, and it attacked a certain proportion of them accordingly. The proportion above the age of five so attacked in 1871-72 was greater than it had been in this country since the beginning of the 18th century; indeed, as the information is not in statistical form for the earlier period, it may be asserted, and it may happen to be true, that it was greater than it had ever been in this country at any time. The reason for the large proportion of adult cases was the same in the rise of smallpox as in its decline, namely, that in the respective circumstances an epidemic found many who had not been through the disease in infancy or childhood. The same happened in those parts of the world where the epidemics of smallpox came at long intervals, during which many had passed from childhood to youth or mature age without once encountering the risk of smallpox.

Such were the epidemics at Boston, New England, and Charleston, South Carolina, in the 18th century. Not only do the accounts of them speak of the disease as if it were mainly one of the higher ages, but it follows from the ratio of attacks to population, known in the case of Boston, that adolescence and adult age must have had a full share, considering that these age-periods included all who were protected by a previous attack. The years of epidemic smallpox at Boston were 1702, 1721, 1730 and 1752: of these four the two worst were 1721 and 1752, the one epidemic following a clear interval of nineteen years, the other a more or less clear interval of twenty-two years:

Smallpox in Boston, Massachusetts[1178].

Population, whites and blacks Attacked by smallpox Died of smallpox Had smallpox before Moved out of town

1721 10,565 5989 844 All the rest less 750 —

1752 15,684 5545 569 5598 1843

These enormous mortalities in Boston were comparable to those of the old plague itself in European cities, not only in falling upon all ages but also in doubling or trebling for a single year at long intervals the annual average of deaths:

Deaths of whites Deaths of blacks Total

1701 146 — 146

* 1702 441 — 441

1720 261 68 329

* 1721 968 134 1102

1722 240 33 273

* 1730 740 160 909

1731 318 90 408

* 1752 893 116 1009

* Smallpox years.

Just as smallpox in its first great outbursts in the London of the Stuarts, or in its rare outbreaks in the American colonies in the 18th century, fell impartially upon children and adults, so in its last outbursts in the London of Victoria it fell upon persons at all ages. The notable thing is, not that smallpox should have of late been attacking adults, for that it has ever done except in times and places in which there were few or no adults who had not been through the disease in childhood; but that it should have ceased to so large an extent to attack infants and children. It has ceased to attack infants and children because other infective and non-infective diseases more appropriate to the modern conditions of the population are attacking them instead. These are measles and whooping-cough, scarlatina and diphtheria, infantile diarrhoea, and the more chronic after-effects of these. The annual death-rate from all diseases under the age of five has fluctuated somewhat per million living from 1837 to the present time, but it can hardly be said that it has fallen much or steadily[1179].

Keeping still to the epidemic of 1871-72, let us consider whether there was any natural or epidemiological reason for its cutting off a smaller ratio of infants and children in its whole mortality than that of 1837-40 did. There had been a most disastrous epidemic of scarlatina for three years just before, which had caused 21,912 deaths in 1868, 27,641 in 1869, and 32,543 in 1870, a total of 82,096 in three years, about two-thirds of which were under the age of five, or at the age-period which smallpox used to be fatal to almost exclusively and to be the greatest single epidemic scourge of. Even in the two smallpox years themselves the scarlatinal deaths were 18,567 and 11,922, of which the share that fell to children under five was one and a half times the deaths in that age-period from the co-existing smallpox. The three years of excessive scarlatina, before the epidemic of smallpox began, had removed large numbers of the class of infants and children who succumb to any infectious disease; if we cannot give the whole rationale of one infection dispossessing or anticipating another, we can at least understand that the earlier and more dominant infection takes off the likely subjects. What scarlatina did egregiously during the three years just before the great explosion of smallpox, it had been doing steadily (along with measles, &c.) throughout a whole generation since the last great sacrifice of infants and children by smallpox in 1837-40. But the fact that scarlatina had in great part dispossessed smallpox among the factors of mortality under the age of five, did not prevent the latter infection from attacking those of the higher ages who were susceptible of it and were at the same time unvexed by any other great epidemic malady proper to their time of life. If the epidemic of smallpox in 1871-72 had cut off as large a ratio under the age of five years as its immediate predecessor in 1837-40 did, its whole mortality would have been about 70,000 more than it actually was. But in no state of the population or of the public health can we suppose that three years of excessive mortality of children by one kind of contagion would be followed immediately by two years of equally special mortality at the same ages by contagion of another kind. It is not only epidemiological science that tells us this, but also common sense—est modus in rebus.

The saving of life by checking the prevalence of smallpox was a favourite rhetorical topic in the 18th century. Voltaire, La Condamine, Bernoulli, Watson, Haygarth and others, were fond of estimating how many thousands of lives might be saved in a year if inoculation were thoroughly carried out. Dr Lettsom, Sir Thomas Bernard and Mr James Neild, who were interested in prison reforms and in whatever else would reduce the prevalence of typhus, reckoned the possible saving of life under that head as almost equal to the possible saving from smallpox[1180]. For typhus there was no artificial means of restraint; it had to decline before natural causes, if it declined at all,—which, indeed, it has done. But no one at that time thought of keeping down smallpox except by the inoculation of itself or of cowpox. The economists and statisticians treated each of these artifices in its turn as a factor having a certain absolute value, which they might use like the a and b of a problem in algebra. This they did, of course, in deference to medical authority. What Bernoulli had worked out for the old inoculation, Duvillard did for the new, in his “Tables showing the Influence of Smallpox on the Mortality of each period of Life, and the Influence that such a preservative as Vaccine may have on the Population and on Longevity[1181].” Malthus fell into the conventional way of thinking when he assumed that smallpox alone among the epidemic checks of population was to be controlled artificially; but he introduced an important new consideration. “For my own part,” he wrote in 1803, “I feel not the slightest doubt, that if the introduction of the cowpox should extirpate the smallpox, and yet the number of marriages continue the same, we shall find a very perceptible difference in the increased mortality of some other diseases[1182].”

Five years after this was written, there came, in 1808, the disastrous epidemic of measles, which in Glasgow killed more infants in a few months than smallpox had ever done at its worst in the same city. In the winter of 1811-12 there was another severe epidemic of measles in Glasgow; and in 1813, Dr Watt, a leading physician of the place, and a man now famous in all countries for his vast labours as a bibliographer, gave to the world his statistical proof, from the Glasgow burial registers, of that law of substitution which Malthus had found necessary in his deduced principles.

“The first thing,” said Watt, “that strikes the mind in surveying the preceding Table (1783-1812), is the vast diminution in the proportion of deaths by the smallpox, a reduction from 19·55 to 3·90. But the increase in the subsequent column [measles] is still more remarkable, an increase from 0·95 to 10·76. In the smallpox we have the deaths reduced to nearly a fifth of what they were twenty-five years ago [in ratio of the deaths from all causes]; in the same period the deaths by measles have increased more than eleven times. This is a fact so striking that I am astonished it has not attracted the notice of older practitioners, who have had it in their power to compare the mortality by measles in former periods with what all of them must have experienced during the last five years[1183].”

The high ratio of measles and the low ratio of smallpox did not remain as Watt’s researches left them. When Cowan resumed the tabulation of figures from 1835 to 1839 he found the ratios of those two infantile infections almost equal, and the two together contributing to the whole mortality of Glasgow only a little more than half their joint share in the end of the 18th century. The substitution which Watt saw during a few years was only the most dramatic part of a general movement forwards of measles among the causes of infantile mortality. He supposed, as everyone did at that time, that smallpox was forcibly repressed, and that another infectious disease had seized the opportunity to become exuberant. The most relevant thing in the whole situation was urged by those who thought, with Jenner, that the doctrine of substitution had an “evil tendency” as detracting from the absolute value of the inoculation principle. In order to discredit Dr Watt altogether, they pointed out that his ratios of smallpox and measles took no account of the diminished death-rate of Glasgow by all diseases in the earlier years of the 19th century.

Great changes were proceeding in the old city, the Glasgow of ‘Rob Roy.’ The population which was reckoned at 45,889 in the year 1785, had increased to 66,578 in the year 1791, and thereafter, at a slower rate, to 83,769 in 1801 and to 100,749 in 1811. The first great increase after the American War meant overcrowding; but in a short time new suburbs spread over such an extent that, in the year 1798, more than half the burials were in the graveyards attached to chapels-of-ease and meeting-houses outside the original parishes. The modern expansion of Glasgow, like that of London and of all other large cities, has been an increase of area still more than an increase of numbers. The public health improved steadily, at all events until 1817, the improvement being shown first in the increasing number of infants that survived their second year. That rise in the probability of life corresponded to the substitution of measles for smallpox, and in part depended upon the ascendancy of the milder infection. Still more remarkable was the rise of scarlatina, which Dr Watt did not live to see; so little was made of it at the date of his writing that he found “scarlatina, typhus, &c., all comprehended under the same head.” The seeds of measles and scarlatina had long existed beside the seeds of smallpox, but the ascendancy of each of the two former had to wait events. Said Banquo to the witches who hailed Macbeth as king and himself as the sire of later kings:

The succession of reigning infections is the same problem. All we can say is that each new predominant type is somehow suited to the changed conditions. In the long period covered by this history we have seen much coming and going among the epidemic infections, in some cases a dramatic and abrupt entrance or exit, in other cases a gradual and unperceived substitution. Some of the greatest of those changes have fallen within the two hundred years since Sydenham kept notes of the prevalent epidemics of London. We are that posterity, or a generation of it, which he expected would have its own proper experiences of epidemics and at the same time would know all that had passed meanwhile—“posteris quibus integrum epidemicorum curriculum venientibus annis sibi invicem succedentium intueri dabitur.”