CO885-8 — Page 250

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PUBLIC RECORD OFFICE

Reference :-

C.O. 885

8.

PUBLIC RECORD OFFICE, LONDON

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2. Mosquitoes. (c) Three bottles containing mosquitoes were placed in

different parts of the cabin near the ceiling.

(d) One bottle containing mosquitoes was placed under a seat

mattress.

3. Pupa of mosquitoes.—(e) One bottle with water containing pupa was

placed on dresser of cabin.

4. Laroa and pupœ of mosquitoes.-(f) One bottle with water containing

larvæ and pupa was placed on dresser.

5.

Grubs and chrysales.—(9) One closed tin tox containing grubs and chry-

sales was placed on rack.

Result.-The bottles containing the bugs, fleas, mosquitoes, mosquito pupæ, and mosquito larvæ and pupa were taken out of the cabin after 11 hours' exposure. Examination showed their contents to be dead. The gas appears to have converted None of them revived. They were kept the bugs and fleas into gelatinous masses. for a fortnight.

The grubs and chrysales were taken out and after two hours' exposure all were dead. They were kept for a similar period.

10. Bacteria of plague, cholera, typhoid, and anthrax.-The third series of experiments was the exposure of pieces of blanket, cloth, cotton, and cotton-wool, which were soaked in cultures of plague, cholera, typhoid, and anthrax, and which were placed in separate test tubes plugged well with cotton-wool. This series was divided into two sets, one in which the material was exposed to the gas in a wet condition, the other in which the material was first dried. Controls were kept for purposes of comparison. Placed about in different parts of the hold, the fact that the material was in test tubes plugged with cotton-wool was of itself a fair trial as to the penetrative powers of the gas, but in order to further test this power, some of the tubes were wrapped in cotton-wool and paper, and others in blankets; two were wrapped in 12 folds of blanket and three folds of a rain-proof cloth coat, and two were placed inside a hair mattress. The results of the experiments are re- corded in the subjoined report of Professor Hewlett and Dr. Willson, who prepared the cultures in the laboratory, placed them under the experimental conditions deter- mined on, and afterwards examined them in the laboratory.

'King's College Bacteriological Laboratory,

King's College, London, W.C.

The germicidal or disinfecting power of the "Clayton" gas was tested by us in the following manner:-Four different materials were first selected, viz., a piece of old blanket, a piece of serge, a cotton handkerchief, and some wool. From these, strips were cut off about 14 inches long and inch broad, and were sterilized by heat. Fresh agar cultures of typhoid, plague, and cholera were emulsified re- spectively in sterile broth, and a fourth emulsion was made with anthrax spores. The sterilized strips of the materials mentioned were then steeped in the various broth emulsions until saturated. In this way some 50 strips were prepared, and 32 of these were at once placed in sterile test-tubes plugged with cotton-wool in the ordinary way. The remainder were kept in the warm incubator (37° C.) for 48 hours, (in order to dry them) before being placed in the test-tubes.

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The experiments on board the S.S. "Manora were carried out on two succes- sive days.

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On the first day, the 32 tubes containing the moist strips were taken to the vessel. Ten of these were picked out to be retained as controls"-three typhoid, three cholera, three plague, and one anthrax. The other 22 were then placed in the after hold of the steamer. Some of the tubes were rolled up in coats and blankets, two were put into a horse-hair mattress, and others were covered with shavings. straw; &c. As regards position, some were placed as near the top as possible, some at the bottom, some "right aft," &c.—the object being, of course, to distribute them in all parts of the hold."

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All being now ready the hatches were closed and the gas from the Clayton

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machine allowed to accumulate to the extent of 10 to 12 per cent. and retained in the hold for a space of six hours.

On the next day, the tubes containing the dried strips were exposed to the gas. This time a small deck cabin was used, and the tubes were wrapped up in blankets, controls." The cabin was closed up and canvas, &c., six being reserved to act as

the gas turned on, 10 to 12 per cent. being used as before.

At the end of the appointed times of exposure to the gas, all the tubes (moist and dry) were removed, and returned, together with the "controls," to the laboratory at King's College.

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Their examination was commenced forthwith.

To the tubes containing the typhoid, plague, and anthrax strips sterile broth was added; for the cholera strips, peptone water was used.

All were then placed in the incubator at 37° C., and kept there for four or five days. They were examined at intervals for the presence of living organisms, by various bacteriological methods.

The results obtained were as follows:-

(1.) Moist strips exposed in hold for six hours. (Six typhoid, six plague, five

cholera, four anthrax spores.)

The typhoid, plague, and cholera organisms were all found to be de- stroyed, irrespective of position and coverings in hold, or of material of which the strips were composed.

The anthrax spores were not destroyed.

(2.) Dry strips, exposed in cabin for four hours.

(Two typhoid, two plague,

two cholera, and one anthrax spores.) Typhoid, plague, and cholera organisms were all found to be destroyed. Anthrax spores, not destroyed.

(3.) Dry strips exposed in cabin for two hours. (Three typhoid, three plague,

three cholera.)

The plague and cholera organisms were found to be destroyed, the strips

in each instance giving negative results.

The

The three typhoid strips were composed two of wool and one of cloth. Two of these, the cloth and one wool, had been wrapped in the same blanket, the other wool strip being rolled up in some canvas. cloth strip gave a negative result, when examined, but both the wool strips gave positive results, showing that some of the typhoid bacilli had survived the two hours' exposure.

(4.) The "controls," when examined, gave positive results for each of the four

organisms.

Conclusions.-Bearing in mind that the infected strips of material were enclosed in glass test-tubes averaging only about inch in diameter, and having the open end firmly plugged with cotton-wool, it must be admitted that the test to which the disinfecting properties of the "Clayton" gas were submitted was a severe one. Nevertheless, in the proportion of 10 to 12 per cent., the gas entirely destroyed the In the case of plague and organisms of typhoid, plague, and cholera, in four hours. cholera, even a two hours' exposure was sufficient to ensure disinfection, but it would seem that typhoid germs in articles of a woollen nature require a longer period than two hours for complete destruction. As for the anthrax spores they are well known to rank amongst the most resistant forms of germ life, and, therefore, we were not surprised to find them survive the action of the gas.

R. TANNER HEWLETT, M.D., M.R.C.P., D.P.H., Professor of General Pathology and Bacteriology

in King's College, London. HOWARD S. WILLSON, B.A., M.B., D.P.H., Demonstrator of Bacteriology, King's College, London.

June 16, 1903.

12. Cultures of plague, cholera, and typhoid destroyed by a four hours and by a six hours' exposure to a 12 per cent. gas. Anthrax not destroyed. It will be seen that the cultures of plague, cholera, and typhoid fever on all the materials in the tubes, whether cotton, blanket, cloth, or cotton wool, and whether in a wet or

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