CO885-8 — Page 251

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سلسيليسيا

PUBLIC RECORD OFFICE

Reference :-

C.O. 885

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PUBLIC RECORD OFFICE, LONDON

ALLY WITHOUT PERMISSION OF THE BE REPRODUCED PHOTOGRAPHIC- COPYRIGHT PHOTOGRAPH—NOT TO

dry condition were destroyed in the hold by an exposure of six hours to an atmos- that in the small cabin they were destroyed phere containing 12 per cent. of the gas, by an exposure of four hours, and that even two hours sufficed to destroy the plague and cholera bacilli, though two hours were insufficient to be fatal to all the typhoid cultures. None of the anthrax cultures were destroyed. These experiments by Professor Hewlett and Dr. Willson, taken together with those made by Dr. Calmette, Director of the Pasteur Institute at Lille, whom I saw a few days ago, and who explained his experiments to me, may be considered to establish the germicidal action of the gas of a strength of 12 per cent. on cholera and typhoid fever and plague when exposed for six hours, and that the gas has no effect on spore-bearing organisms such as anthrax.

Dr. Calmette found that dry cultures of streptococcus and of typhoid bacillus mixed with or without blood serum were destroyed by exposure for six hours to an eight per cent., 10 per cent., and 12 per cent. concentration of the gas generated by a Clayton's Machine; that these percentages also destroyed dry cultures of diphtheria bacillus without admixture of serum, but that only a 12 per cent. was effective The gas has no action on the when the diphtheria bacillus was mixed with serum. tubercle bacillus or on anthrax, or on the dust of sweepings. On the other hand he found that both plague and cholera were destroyed even by a two hours' exposure to an eight per cent. gas.

The gas has been analysed in the Pasteur Institute of Lille by Dr. Rolante, Chemist to the Institute who showed me the method which he adopted. In addition to sulphurous acid, every litre of the gas contained 6 milligrammes of sulphuric anhydride against,of a milligram:ne contained in a litre of gas obtained by burn- There were other unstable ing sulphur in the open air under ordinary conditions. compounds of sulphur and oxygen, the exact nature of which has not been deter- mined.

13. Meat and food-stuffs.-The fourth series of experiments was arranged Two frozen to ascertain the effect of the gas on meat and different food-stuffs. and two unfrozen legs of mutton, and quantities of green coffee, roasted coffee, rice and flour were exposed in bags to the gas for six hours, together with a number of articles, such as flour and rice in the kitchen drawers, for periods between two and four hours. None of the exposed articles underwent any important changes. The flour retained the smell of the gas for a short time, but lost it quickly when exposed to the air; the green coffee, roasted coffee, tea and rice had no perceptible smell after being taken out of their bags. The tea made with the leaves which had been exposed to the gas was excellent, and it was impossible to discern any difference in the taste. The meat was slightly dried on the surface, but otherwise showed no change. The two legs of mutton which were frozen, and one of the unfrozen, remained in excellent condition during a fortnight's exposure in King's College bacterio- logical laboratory. They were then cooked and eaten, and pronounced to be tender and delicious. The other unfrozen leg of mutton began to have a stale smell on the eighth day after being taken from the hold, and two days later moulds were noticed on a part which had been cut into. It remained in this condition for a fortnight, when it was thrown away. Two other legs of mutton were kept as con- trols and not exposed to the gas; they were stale on the fourth day, and covered with moulds, and were putrid on the eighth day. The preservative effect which the gas evidently has-on meat is likely to prove of great value.

14. General merchandise and fabrics.-The fifth experiment was to expose to the action of the gas for six hours :--

(1.) Two books with leather binding with gilt letters and edges.

(2.) Photographs and coloured reproductions, bromide photographs hand-

painted.

(3.) Samples of coloured flannelettes wrapped in paper.

Coloured printed diagrams, chromo-lithographs and cardboard painted

matter.

(5.) Doe-skin gloves, wearing apparel, shoes, fur muff and fur boa wrapped

in paper.

Cigars, cigarettes, biscuits, whiskey in well-corked bottles.

Samples of delicate coloured silks wrapped in paper: mauve, violet, light blue, dark blue, yellow, green, red, tartans, and plaids of all colours. Between the leaves of the books, the photographs, and between the samples of

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coloured flannelettes and coloured silks, strips of blue litmus paper were placed to test the penetrative power of the gas, which possesses the property of changing the blue colour of the litmus into red. The result of the experiment was that in every case the blue litmus paper was changed into red. Even the litmus which was contained between the leaves of the closed books was affected, which showed that the gas under very exceptional conditions possessed powerful penetrative properties. But although the blue litmus was changed into red, neither the leather binding, gilt lettering, nor gilt edges of the books were affected, nor were the photographs or coloured diagrams, or lithographs, or furs; in fact, none of the articles or fabrics were affected. Controls were kept of the samples in every case for comparison, and a careful examination afterwards exhibited no change in any of the articles exposed. There was no bleaching and no injury. The only sample which was an exception to the others was a delicate blue silk, which showed, after exposure, a slightly paler blue hue than the sample not exposed. With this exception the others remained, as far as a careful examination by Professor Hewlett, Dr. Willson, and myself, unchanged, and the same as those unexposed to the gas.

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Furniture of Cabins and Saloons and Machinery in Engine-rooms.—On the third day after the ship had been fumigated in every part an inspection was made in order to examine the condition of the cabins and saloons, engine-room and other parts of the ship. The result of inspection was highly satisfactory in that no damage had been caused by the fumigation. The white paint of the cabins and corridors and saloons, the different coloured plush cushions of settees and chairs, the red table cloths, the carpets, punkahs, book-cases, piano, varnish work, pillars and gilt orna- mentation were unaffected. The only articles that were tarnished but not damaged were the brass and silver work, which were easily re-polished to their former condition by rubbing with a little plate powder.

Some of the silver and brass work had been covered previous to the fumigation with a little whitening as a precaution. This sufficed to prevent them from being tarnished.

As regards the machinery in the engine-room, the steel work was discoloured and every metallic surface had the appearance of not having been cleaned for a week. The discolouration was, however, only on the surface, and everything resumed its original polish when cleaned with a little bath brick and oil.

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Conclusions. From the foregoing experiments and observations it may be concluded that:--

(1) The gas generated from the Clayton furnace and saturating a compartment

to the extent of 10 and 12 per cent. is a toxic gas.

(2) That a six hours' and even a four hours' exposure to a 10 per cent. or 12 per cent. gas will be fatal to rats and insects such as cockroaches, bugs, fleas, and grubs, and to mosquitoes and mosquito larvæ and pupæ. As a matter of fact all these are destroyed by a much shorter exposure to the gas.

(3) That a similar exposure is destructive to the vitality of the bacillus of plague, cholera and typhoid fever, but has no action on the spores of anthrax.

(4) That the gas is a preservative of meat and not injurious to food-stuffs. (N.B. I am informed, however, that fruits are damaged by the action of the gas.)

(5) That merchandise, such as dyed silks, print stuffs, books, photographs,

tea, coffee, &c., are unaffected by exposure to the gas.

(6) That upholstering stuffs and machinery sustain no damage from the gas, but that metals are tarnished and afterwards require to be cleaned, when they regain their former appearance.

These are very important facts, confirmed as they are by independent experi- ments elsewhere. The properties, thus ascertained, render the gas invaluable for the prevention and spread of plague by infected rats and vermin, and for the spread of malaria and yellow fever by infected mosquitoes. It is, moreover, not only valuable for the destruction of the carriers of disease, but it possesses the additional advantage of being fatal also to the causal agents or bacilli of plague, cholera and typhoid fever.

It can be therefore employed as a germicide for these particular diseases, as well as a vermin killer. Independently of being useful for combating

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