SECTION IV.—Part VI.—Protozoa (Psorospermiæ, Gregarinidæ, &c.).

The scope of this work does not demand that I should comprise within its limits any vegetable parasites; nevertheless, I must needs refer, however briefly, to certain confervoid and sarcodic organisms, which, for the most part, lie on the borderland of the animal and vegetable kingdoms. Professor Cohn regards the bacteria as allied to the Oscillitoriaceæ. He puts them in his order Schizosporeæ. It is of little moment, practically, where these protista forms are placed. Unquestionably many of them are parasitic, as they live in the tissues, fluids, and secretions of animal bodies, including man. Their presence in cattle is associated with an anthracoid disease (charbon), whilst in the human body they have been detected in connection with zymotic affections. They have been found by Cohn, Sanderson, Klebs, Chauveau, and others, either in the lymph of vaccine pustules, or in the miliary eruptions of typhus fever. Professor Beale, who was one of the first to observe these special organic particles in vaccine lymph, denies that they are true Bacteria; and, indeed, he warmly disputes the inferences that have generally been drawn from the fact of the presence of such particles in lymph, blood, and other nutrient fluids. The best known and defined forms are Bacterium termo and Bact. lineola, which are concerned in the production of putrefaction, Bacillus anthracis, found in the blood of animals suffering from carbuncular disease, Micrococcus septicus, found in typhus and pyæmia, M. vaccinæ of cow pox lymph, and M. diphthericus, in diphtheria. As regards their prevalence in certain forms of relapsing fever, Sanderson states that Dr H. V. Carter, of Bombay, examined the blood of 250 fever patients and found spirilla in nearly every instance. From the independent observations of Pasteur, Sanderson, Lister, Tyndall, Bastian, Eberth, Roberts, Davaine, and many others, it seems clear that the Bacteria and their allies play an important part in association with certain morbid states. However, as regards the etiology of the maladies in which these organisms are found, it is perhaps too early to speak with absolute confidence. The subject cannot be dealt with here; moreover, it is outside the range of my personal investigations.

Passing to those protozoa which, although retaining some vegetable affinities, are more or less distinctively animal, I notice the obscure organisms termed psorosperms. In dealing with these I shall treat of the forms that infest both man and animals, confining my remarks to such as happen to have come under my own observation.

In the year 1865 the public were thoroughly roused to a sense of danger arising from the consumption of meat. The panic originated with the outbreaks of trichiniasis in Germany. During the excitement which subsequently prevailed at the time of the rinderpest, all sorts of erroneous notions took possession of the popular mind, and the errors were stimulated by writers ignorant of helminthology. In January, 1866, I published a few observations, the purport of which was to show that certain microscopic organisms found in animals dying from cattle plague were harmless “parasitic Protozoa,” possessing more or less striking vegetable affinities. About a week previously some interesting researches on these so-called cattle-plague bodies had been published by Dr Beale. Those who first saw these bodies thought they had stumbled upon organisms new to science. I showed that similar or analogous organisms were to be met with in a great variety of animals, and likewise in the human body. They had been called worm-nodules, worm-nests, egg-sacs, eggs of the common fluke, young “measles,” corpuscles produced by muscular degeneration, psorospermiæ, stages of growth of gregarinæ, amœboid bodies, and so forth. In so far as the higher animals were concerned, Dujardin was the first to describe them. He found these organisms in a mole. This animal, however, having been fed upon earth-worms known to harbour such parasites, there was no difficulty in accounting for the source of the psorosperms.

In 1853 Hessling discovered psorospermial sacs in the muscular substance of the heart, not only of the ox, but also of the sheep and roe. By him they were regarded as evidences of muscular degeneration. About ten years previously Miescher found similar bodies in the muscles of the mouse.

In 1857 Rainey described similar structures taken from the flesh of swine; and, in his memoir, he went so far as to maintain that these bodies were early stages of development of the common pork-measle. In the year 1858 Gubler wrote an important paper on this subject, in which he related a case where twenty cysts existed in the human liver. The cysts were of great size, mostly as large as a hen’s egg, one of them being some six inches in diameter. Naturally, the largest had been diagnosed as an ordinary hydatid. However, on evacuating their contents (post mortem), they were found to harbor enormous quantities of minute corpuscles strictly analogous to those usually obtained from psorospermial sacs. Gubler believed he had stumbled upon masses of eggs of Distoma hepaticum, but in this he erred. Shortly after Gubler’s discovery similar bodies from the human liver were described by Virchow; and in 1862, the subject was followed up by Dr Dressler, of Prague. Dressler found in the human liver a number of pea-shaped bodies, the milky contents (breisubstanz) of which displayed a multitude of the characteristic corpuscular elements referred to. These particles, already considered as equivalent to, if not identical with, the so-called pseudo-navicellæ of gregarinæ, were soon encountered by a variety of independent observers. Thus, Leuckart noticed these bodies in various animals; but with caution remarked:—“Concerning the nature of these formations I will not decide. To be candid, however, it appears to me to be in no way made out whether the psorospermiæ are to be considered as the result of a special animal development, whether they, like pseudo-navicellæ, are the nuclei of gregariniform productions, or whether they are the final products of pathological metamorphosis.” Leuckart found these organisms in the intestines of a trichinised dog, also in a sheep and pig fed with Trichinæ. He also found them in the muscles of another pig fed with psorosperms, and likewise in the liver of various rabbits. He remarks that in swine these parasites are more abundant than measles. They were present in five of eighteen pigs, and also in two out of four sheep, whose flesh was especially examined. The observations of Lindemann at Nischney-Novgorod are particularly interesting. This medical officer discovered psorospermial sacs attached to the hair of a girl who was being treated in hospital for chlorosis. The sacs in question bore close resemblance to the bodies which we found in abundance in diseased and healthy cattle. It would further appear, from Lindemann’s observations, that the affection is not very uncommon amongst the Russian peasants.

In connection with and attached to the same parasitically affected hairs Lindemann also noticed several movable gregarinæ; and partly from this circumstance he was led to believe in the existence of a genetic relation subsisting between the two kinds of bodies. He further expressed his conviction that the people contracted the disease by washing themselves with water in which gregarinæ abounded. Lindemann moreover refers to Lebert as having noticed similar parasites in a case of favus, and concludes that these organisms are of a vegetable nature. His opinion, though not shared by the majority of parasitologists, is nevertheless supported by the views of Robin, Leydig, and others. Of still higher interest are the observations of Lindemann respecting the occurrence of psorospermiæ in the capsule of the kidney of a hospital patient who died with Bright’s disease. The sacs in this case were remarkably small; nevertheless their corpuscular contents indicated their true nature. The pseudo-navicellæ measured only 1/5000″ in diameter. Amongst other contributions of interest I may refer to those of Dufour, J. Müller, Creplin, Kölliker, Keferstein, Stein, Drummond, Lieberkühn, and E. Ray Lankester. I doubt if the vegetable organisms described by Prof. W. T. Gairdner can be referred to this group of parasites. At all events, by whatever name these spurious entozoa are called, they were first discovered by Dufour in insects, by Müller in fishes, by Miescher in the mouse, by Dujardin in the mole, by Hessling in the larger quadrupeds, and by Gubler in man. The results of my own examinations may be briefly re-stated. In the flesh of cattle I found psorospermial sacs varying from 1/120″ to 1/12″ in length, and in that of sheep from 1/220″ to 1/80″. The bodies were enclosed in well-defined transparent envelopes, and their contents exhibited indications of segmentation. In some specimens the segments displayed themselves as a complete cell-formation, the contents of each cell being uniformly granular. Under the 1/4″ objective the contained granules were clearly visible, and on rupturing the sac their peculiar characters were at once manifest, each granule or corpuscle represented a pseudo-navicel, all displaying a tolerably uniform size, averaging 1/2000″ in diameter. Some of the corpuscles were round, others oval, several bluntly pointed at one end, many curved and fusiform, not a few being almost reniform. Highly refracting points or nucleoli were visible in their anterior.

Turning to the practical aspect of the subject, I remarked that these bodies had nothing to do with the cattle plague. No one who carefully examined the flesh of animals that had died of rinderpest had failed to discover them; yet, in one or two instances they appear to have escaped notice. When it is considered how long it takes us to examine a few grains weight of muscle carefully, it is obvious that the body of a large beast might contain many hundreds of these organisms without our being able to detect their presence, except by a prolonged investigation. In the few rinderpest beasts, portions of whose flesh I submitted to the microscope, I should say there were not more than 100 of these bodies in one ounce of meat; but in the heart of a healthy sheep (which I afterwards ate) I calculated there were about 1000 parasites to the ounce, and in the heart of a healthy bullock (which likewise served me for a meal) their numbers were rather in excess of those in the sheep. Altogether, at two meals, I could not have swallowed less than 18,000 of these psorosperms. Consumers of beef, mutton, and pork eat these bodies every day, but they take no harm because the parasites in question are not true helminths. Fine healthy beef has been returned to the butcher when it was as good as any other meat in the market. I have examined various kinds of meat, such as veal, pork, and mutton, but in none have I found so great an abundance of psorosperms as in beef, which was, notwithstanding, perfectly healthy and sound. I calculated that in one instance a single ounce of the flesh contained upwards of 2000 parasites. There is practically no limit to the extent of this kind of parasitism, and there is no organ of the body in which psorosperms may not be found. Moreover, the forms they display are exceedingly various. Psorosperms have been found by Siedamagrotzky in the muscles of the horse, and not very long ago, through the help of Professors Simonds and Axe, I had the opportunity to examine some peculiar worm-like structures which occupied the mitral valve of a horse. To the naked eye they looked like coiled nematodes, but I was soon convinced that they formed a peculiar type of psorosperm. A complete view of these bodies was a matter of great difficulty owing to the delicate nature of their limiting membrane and to the confusion of markings produced by the interlacing of the fibres of the chordæ tendinea. At length, by spreading a portion of the membrane of the valve over a large glass slide, and by allowing it to dry slowly, I found that the vermiform body presented neither beginning nor end. The appearances were curious and puzzling. The organism formed a flattened tube or sac, almost uniform in width and variously twisted upon itself. From the main tube there projected several hernia-like secondary loops or branches, most of them presenting less than half of the thickness of the former. These peculiarities, however, can hardly be understood without reference to the original illustrations. That these secondary coils were not of the nature of hernial protrusions was evident, not alone from the nature of their contents, but also from the fact that they showed distinct anastomoses. In fact, the parasite was a simple sac or bag with branches.

On puncturing the main tube with a fine needle a small quantity of tenacious creamy fluid made its escape. This, under Ross’s 1/4-inch lens, resolved itself into a few excessively delicate sarcode globules surrounded by fine granules. The granular matter displayed a tendency to collect itself in the form of oval masses without showing any trace of a limiting border. One of these masses, measuring 1/250″ in length, I examined under a Wasserlein-objective, when I further ascertained that the elementary particles or granules were uniformly oval in shape, rather highly refractive, their size scarcely exceeding 1/8000″ in diameter. The sarcode corpuscles, on the other hand, were of different sizes, ranging between 1/3000″ and 1/1600″ in diameter.

From the facts thus elicited, negative as they were in respect of helminthic structure, I could see no escape from the conclusion that we had to deal with a new form of psorospermial bag, whose granular contents consisted of excessively minute pseudo-navicellæ. In the centre of the largest hernia-like loop there was a clear oval disk, which at first brought to my mind the nucleus of Monocystis infesting the earth-worm, but it was merely a vacuole.

The case recorded by Gubler reminds me of another remarkable instance of psorospermial cysts, in this case associated with true hydatids. In 1873 Dr Whittell sent me particulars of a case in which the contents of an hydatid of the liver (drawn off, during life) consisted of shreds of a true hydatid, a few echinococcus-hooklets, together with multitudes of spindle-shaped amœboid particles of excessive minuteness and delicacy. The bodies, floating in a transparent fluid, formed a thick milky or creamy fluid, resembling pus in appearance; but there was no trace of pyæmia. Judging from Dr Whittell’s figures, he must also have found a solitary microscopic nematoid hæmatozoon, the nature of which was not clear to him. I believe it to have been a specimen of Filaria sanguinis hominis. Be that as it may, the case is altogether unique and deserves further elucidation.

As regards the higher forms of protozoa it must suffice to allude to the Cercomonas hominis of Davaine, found in the dejections of cholera patients, to the Cerc. urinarius of Hassal and C. saltans of Ehrenberg, to the Trichomonas vaginalis of Donné, detected in the vaginal mucus, and to the Balantidium coli of Claparède and Lachmann, originally found by Malmsten in the human colon. The Balantidium, or Paramæcium coli, has frequently been observed in the evacuations of fever patients, and it has also been found by Dr Treille in patients suffering from the Cochin-China diarrhœa. Monads have also been found in the stomach and intestines of the hog and various other animals. Infusorial parasites are particularly abundant in batrachians, the Bursariæ of frogs and toads being familiar to every helminthologist.

Bibliography (No. 41).—Arloing (and Tripier), in ‘Gaz.-hebd.,’ 1873, p. 574 (quoted by Davaine).—Balbiani, ‘Compt. Rend. Soc. Biol.,’ 1867, p. 103 (quoted by Davaine and Bastian).—Bastian, “On the Nature of the so-called Sarcina ventriculi,” ‘Brit. Med. Journ.,’ Feb. 3, 1872.—Idem, “On Heterogenesis in its relation to certain Parasitic Diseases,” ‘Brit. Med. Journ.,’ Feb. 24 and April 20, 1872 (see part iv, p. 417, with figs. from Balbiani).—Beale, L., “Entozoon-like bodies in Muscles,” in the ‘Microscope in Medicine,’ 4th edit., p. 485, 1878.—Idem, “Bacterium Hypothesis of Contagium,” ibid., pp. 313–321.—Burnett, W. T., “On Psorospermia, Mermithes, &c.,” in a paper entitled ‘Reviews and Records in Anat. and Physiol.,’ in ‘Amer. Journ. of Sci. and Arts,’ vol. xviii, 2nd ser., p. 104, 1854.—Carter, H. V., “On Spirilla,” quoted by Sanderson in ‘Brit. Med. Journ.,’ Nov. 17, 1877, p. 700.—Cobbold, “Remarks on Spurious Entozoa found in Diseased and Healthy Cattle,” ‘Path. Soc. Trans.,’ vol. xvii, p. 452, 1866, and ‘Lancet,’ Jan. 27, 1866, p. 88; see also Prof. J. Gamgee’s work on the ‘Cattle Plague.’—Idem, “On Worm-like Organisms in the Mitral Valve of a Horse,” ‘Veterinarian,’ Sept., 1877.—Idem, “On Psorospermiæ in the Eye of the Cod (Morrhua),” ‘Linnean Society’s Proc.,’ May, 1862, and in ‘Intellectual Observer,’ 1862, p. 199.—Cohn, ‘Nova Acta,’ xxiv, s. 103 (quoted by Leuckart), Bd. i, s. 139.—Creplin, ‘Wiegmann’s Archiv,’ 1842, s. 61.—Davaine, l. c., 2nd edit., “Synops. xxi” (with bibliog. refs.), 1878.—Donné, ‘Cours de Microscopie,’ Paris, 1847, p. 157.—Dressler, quoted by Leuckart, Bd. i, s. 141.—Drummond, ‘Edin. Phys. Rep.,’ 1852,—Dufour, ‘Ann. des Sci. Nat.,’ 1837.—Dujardin, ‘Traité’ (l. c., see Bibl. No. 1).—Eberth, ‘Zur Kentniss Bacteritischer Mykosen,’ 1872.—Eimer, ‘Ueber Psorospermien,’ 1870.—Gairdner, ‘Edin. Phys. Soc. Rep.,’ 1853.—Gluge, “Cysts in Sticklebacks,” ‘Bullet. Acad. Roy. des Sci. de Bruxelles,’ 1838.—Gubler, ‘Mem. Soc. Biol.,’ 1859, p. 657, and in ‘Gaz. Méd.,’ 1858, p. 61.—Harz, C. O., “Eine neue Mikrococcusform im lebenden Thierkörper,” ‘Deutsche Zeitschrift für Thier-Medicin und vergleichende Pathologie,’ f. Novemb., 1878.—Hessling, ‘Sieb. u. Köll. Zeitsch.,’ 1853, p. 196.—Henle, ‘Müller’s Archiv,’ 1845.—Hollis, W. A., “What is a Bacterium?” repr. in the ‘Veterinarian,’ p. 205, 1875.—Keferstein, ‘Götling. gelehrte Anzeigen,’ 1862.—Kloss, ‘Ueber Parasiten (u. s. w.)’ (quoted by Davaine).—Knoch, ‘Journ. de Russ. Kriegs. dep.,’ Bd. xcv, 1866 (quoted by Leuckart and by Davaine).—Kölliker, in ‘Zeitsch.’ (by Sieb. and Köll.), 1848–49.—Lambl, ‘Prager Vierteljahrschrift,’ 1859.—Lankester, E. R., “Recent Researches on Bacteria (with copious references),” ‘Quart. Journ. Micr. Science,’ Oct., 1878.—Lebert, ‘Phys. Pathologique’ (quoted by Leuckart).—Leidy, “Gregarina,” ‘Amer. Phil. Trans.,’ 1851.—Leisering, “Bericht (u. s. w.),” in ‘Sachsen,’ 1865.—Leuckart, l. c., Bd. i, s. 135 and 740, and Bd. ii, s. 842 et seq.—Leydig, ‘Müller’s Archiv,’ 1851, s. 221, in ‘Micr. Journ.,’ 1853, p. 206, and in ‘Arch. f. Anat. und Phys.,’ 1863, s. 191.—Lieberkühn, ‘Müller’s Arch.,’ 1854.—Lindemann, ‘Bullet. Soc. imp. des Naturalistes de Moscow,’ 1863, and in ‘Gaz. Méd. de Paris,’ 1870, p. 86.—Lister, J., “Natural History of Bacteria,” ‘Micr. Journ.,’ Oct, 1873.—Malmsten, “Paramæcium coli” (quoted by Davaine, l. c., 2nd edit., p. 67).—Miescher (quoted by Leuckart and Siebold).—Müller, ‘Archiv,’ 1841, s. 477.—Rainey, ‘Phil. Trans.,’ 1857.—Rayer, “Singulière éruption sur un véron (Cyprinus),” ‘Arch. de Méd. Comparée,’ Paris, 1842 (quoted by Davaine).—Rivolta, “Psorospermi, &c.,” trans. in ‘Journ. des Vét. du Midi,’ 1869, pp. 445 and 521.—Robin, ‘Les Végét. Paras.,’ 2nd edit., p. 291.—Sanderson, in ‘Privy Council Reports,’ 1874.—Siedamagrotzky, in ‘Recueil de Méd. Vét.,’ 1872, p. 460.—Stein, in ‘Müller’s Arch.,’ 1848, and ‘Ann. Nat. Hist.,’ 1850.—Idem, “Abhandl. d. k. Böhmischen Gesellsch.,” x, s. 69, oder Lotos, 1859, s. 57 (quoted by Leuckart, Bd. i, s. 151).—Steinberg, ‘Walter’s Zeitschr. f. die moderne Medicin,’ 1862, and in Leuckart, Bd. ii, s. 844.—Stieda, ‘Arch. f. pathol. anat.,’ Bd. xxxv, and in Leuckart, Bd. ii, s. 846.—Suriray, “Sur quelques parasites du lombric,” ‘Ann. des. Sci. Nat.,’ 1836.—Virchow, “Zur Keutniss der Wurmknoten,” ‘Arch. f. Anat. u. Phys.,’ xviii, s. 523.—Vogel, ‘Path. Anat.,’ i, s. 404.—Waldenburg, “Psorospermien,” in ‘Arch. f. Path. Anat.,’ s. 435, 1867.—Windbladh, also Wising, ‘On Balantidium coli’ (quoted by Leuckart, Bd. ii, s. 846–847).—Winkler (see Leisering).

Appendix.—On various occasions I have dwelt upon the necessity of acquiring accurate information respecting the degree of mortality due to parasites, and in the present volume (p. 124) I have referred to the defective evidences supplied by the returns of the Registrar-General in respect of the echinococcus disease. My object is not to cast blame upon those whose duty it is to publish the returns, but rather to call attention to the advantages that would follow if the Registrar-General were supplied with full and accurate information on this head.

Through the courtesy of Mr Noel A. Humphreys I have been furnished with the following official statement of the number of Deaths from Worms in England and Wales, as recorded in the Annual Reports of the Registrar-General throughout a decade of years:

1868186918701871187218731874187518761877

Total172148151160154183188227204225

Including—

Porrigo15131919191415161713

Scabies161217111412—151213

Tapeworm18131613151315151216

Hydatids20203337413429433151

Considering the prodigious advances in helminthology during the last half century, it is certainly remarkable that under the category of “worms,” as a cause of death, only two kinds of true helminths should be mentioned in the Registrar’s record. It will also strike the experienced hospital and dispensary physician as somewhat remarkable that of the two death-producing parasites above named one of them should be the “tapeworm.” Now death from Tænia is certainly a very rare occurrence, although grave nervous symptoms are not unfrequently due to its presence in man. Thus, I am inclined to regard the 46 reported instances of death from this cause as a redundant estimate. On the other hand, I am surprised to see no specified instances of death from lumbricoid Ascarides, from Oxyurides, or even from Cysticerci, which now and then take up their residence in the human brain.

As regards hydatids I believe the returns to be excessively deficient. In place of an average of 34 deaths annually from this cause in the United Kingdom I am of opinion that at least 400 deaths are due to hydatids. This opinion and the data on which it was founded were communicated by me twelve years ago to the Linnean Society, and I have since become acquainted with facts which lead me to conclude that my original estimate was very much below the mark. The post-mortem registrar of one of our large hospitals has told me that of late years as many as ten deaths might be reckoned as annually due to hydatids in their institution alone. At a smaller hospital I ascertained that the average was about four. Obviously, if these estimates are correct, the Registrar-General’s returns for the United Kingdom do not record a tithe of the annual mortality due to hydatids. Perhaps another half century will elapse before the truth of my deductions be confirmed by the official returns. For me, it must suffice to have pointed to the desirability of securing more accurate records.

By a curious coincidence I had only just sent to press the sheet of this work recording the statistics of hydatid disease in Australia (p. 123), when a paper dealing with the same subject appeared in the ‘Lancet.’ I refer to the brief memoir of Dr David Thomas, of Adelaide, South Australia, which was published on the 1st of March, 1879. Dr Thomas writes as follows:

“It is well known that Australia presents an extraordinary prevalence of hydatid disease, but, as far as I know, no definite statistics have been published to illustrate the fact. Consequently, some months ago, with the kind assistance of the Hon. W. Morgan, the present Chief Secretary of South Australia, I endeavoured to procure reports from the Governments of Victoria, New South Wales, Queensland, New Zealand, Tasmania, and Western Australia, upon this question. Unfortunately, the mode of registration of the causes of death in most of these colonies was such as prevented the necessary replies being supplied. However, it appears that in Tasmania no deaths were returned from this disease in the ten years 1867–77. During the greater part of the same period no separate classification of hydatid disease had been adopted in New South Wales; but in 1875 four deaths were attributed to hydatids; in 1876, eleven were so returned. In Victoria, however, the record of deaths from this cause is far more complete, and I append a table based upon the returns from that colony.

“One case, in which hydatid of the kidney was present, accompanied by malignant disease of bladder, with stricture, was not returned as a case of hydatid causing death.

“During the decade 1867–77, 2·5 per 1000 deaths were due to hydatid disease. In 183 out of the 307 cases the liver was either solely or conjointly with other organs the seat of disease. Holding the second place in frequency come the lungs in 71 cases, i.e. 53 simple and 18 complicated.”

Table of Deaths returned as being due to Hydatid Disease in the Province of Victoria during the ten years 1867–77.

Year.Liver.Lungs. and pleura.Brain and spinal cord.Heart and peri- cardium.Kidney.Spleen.Pan- creas.Omen- tum.Ovary.Womb (?)Abdom- inal cavity.Situation not recorded.More than one organ invaded.Total annual deaths.

186811715112171(a)33

1869116181112113(b)22

18701101211417

187111416111111(c)15

1872119131112121(d)29

1873117132125(e)29

18741211011162(f)41

18751291721113122(g)47

187612311211145(h)36

18771201811113122(i)38

Totals1665375232111?133122307 in 10 yrs.

(a)Lungs and kidneys.

(b)In two instances liver and lungs; in the third case liver and brain.

(c)Lungs and liver.

(d)Lungs and abdominal cavity.

(e)In three cases liver and lungs; in one kidney and abdomen; in another liver, lungs, omentum.

(f)Liver and lungs.

(g)One liver and lungs; the second case lungs and heart.

(h)Three cases liver and lungs; one liver and kidney.

(i)Liver and lungs.

Such are the returns as recorded by Dr Thomas. If a comparison be instituted between the data supplied by his decade-report and those supplied by the decade-report which I have previously adduced (p. 123), it will be seen that as regards the returns for the years 1868–72, inclusive, both reports are in perfect agreement. Of still more interest also is the circumstance that whilst, on the one hand, out of the total of 307 deaths given in Dr Thomas’s table, 116 occurred during the first semi-decade (i.e. from 1868 to 1872, inclusive), on the other hand, no less than 181 deaths occurred during the second semi-decade (i.e. from 1873 to 1877, inclusive). This increase of 45 deaths during the later semi-decade is very significant. It points either to the fact of more careful returns having been made, or to an actual increase in the fatality of the disorder. Possibly both the causes alluded to operated to affect the returns. Be that as it may, Dr Thomas’s record is highly instructive, and should stimulate the profession in England to supply our Registrar-General with more precise data wherewith to construct his annual reports.