Note 4 — Correspondence.

The cattle show at the Agricultural Hall, Islington, has for the two last years been successfully disinfected and kept sweet with carbolic acid.

Had Mr. Sutton ever seen carbolic acid fumigation, or read about carbolic acid, he would not have made an assertion so utterly groundless. The writer has himself many times been for two or three days together in a room containing a large excess of carbolic acid fumes without experiencing any injurious effects.

With regard to the action of carbolic acid on the teeth, if Mr. Sutton will refer to an article in the British Journal of Dental Science for March, 1871, he will find “it is a powerful antiseptic, and invaluable for the arrest of any decay or decomposition of the teeth.”

Mr. Sutton has quoted from a long letter of Dr. Dougall’s to the Lancet, and I cannot do better than refer him to Dr. Sansom’s able reply to it in the Lancet of January 13th. Dr. Sansom says that the white-cloud appearance in albuminous solutions to which carbolic acid has been added is often really no albuminous precipitate at all, but is caused by refractile globules of carbolic acid in a fine state of sub-division; also, that it has been shown that albuminous solutions are antisepted when carbolic acid exists in them in too feeble a proportion to cause any precipitate whatever. If carbolic acid acted as an antiseptic by coagulating albumen, agents which had a greater coagulating power would, a fortiori, be more powerful antiseptics, which has abundantly been proved not to be the case, and therefore the antiseptic properties of carbolic acid do not result solely from its power of coagulating albumen.

With respect to the assertion that the amount of carbolic acid vapour which could be tolerated in the air of a hospital ward would be entirely inadequate to act as a disinfectant, Dr. Sansom says his experiments have shown him that carbolised atmospheres are efficient in preventing putrefaction and the growth of mouldiness, and more so than atmospheres impregnated with chloride of lime or sulphurous acid.

Dr. Sansom objects to the experiments recorded by Dr. Dougall, since tar oil (a crude product weak in carbolic acid, and possessing little or no volatile disinfectant constituent), and McDougall’s powder (a mixture of sulphites of lime and magnesia with tar oil) were used.

As to carbolic acid not being a good antiseptic, the following reports, I think, fully prove the contrary:—

The late Dr. W. Allen Miller, F.R.S., preserved urine and fresh blood for three months by the simple addition of five per cent. of Calvert’s carbolic disinfecting powder—a product containing fifteen per cent. of carbolic acid in a free state.

Mr. Wm. Crookes, F.R.S., says that he took some albumen from fresh eggs and mixed it with an equal bulk of water. By itself it became bad after nine days, and at the end of three weeks it smelt very strongly. He added to four bottles of the fluid respectively 1, 2½, 5, and 10 per cent. of carbolic acid powder (equivalent to 3/20, ⅜, ¾, and 1½ per cent. of free carbolic acid). All kept good at ordinary temperatures for forty days. Blood with 1/15 per cent. of carbolic acid remained good for a month. Solutions of size, glue, and gum mixed with 1/15 per cent. of carbolic acid have remained for two months without becoming sour. Fresh yeast was washed with water containing one-tenth per cent. Its power of inducing fermentation was entirely destroyed.

Dr. F. Crace Calvert, F.R.S., in his paper on comparative disinfectants, gives the following results with antiseptics upon solutions of albumen:—

Antiseptic employed. Percentage of antiseptic used. Time in which acquired an offensive odour. Temperature 70° to 80° F.

Chloride of lime 5 16 days.

Tar oil 2 11 days.

Carbolic acid 2 remained sound six months

None — 5 days.

The writer preserved meat for ninety days, during a hot summer, by placing twelve ounces of fresh meat in a bottle containing one pound of water and five grains of carbolic acid. The mouth of the bottle was left open, and no offensive smell was emitted till the ninety-third day. The meat was, of course, unfit for food, and was merely experimented with to test the antiseptic power of carbolic acid.