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PUBLIC RECORD OFFICE

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are preserved in the Museum of the Chamber of Commerce of Dunkirk along with the controls. In this report Dr. Duriau mentions as a fact to be specially noted, that at Dunkirk all the merchants, shipowners, brokers and forwarding-agents praise the new method of disinfection. In a note by Messrs. Proust and Faivre dated 10th March, 1893, which appears in an authorised reproduction of their original report, they remark that "it results then from this experiment and from others of a similar nature, the results of which have been brought to our knowledge, that the 'Clayton ' gas does not injure delicate substances such as textile fabrics when they are protected by wrappings from its direct action, while at the same time it manages in an incon- testible manner to come into contact with them." I may refer also to the endorsement of the Colonial Ministry in the "Annexe aux Annales D'Hygiène et de Médicine Coloniale" that appeared in April 1903.

In connection with the statement of slight bleaching in one instance of coloured silk I mention in my report that out of 150 samples of delicate coloured silks three In every case when any bleaching were slightly changed in tint but not bleached. occurred it was when the fabric was directly exposed to the gas, and it suffices to protect the most delicate shade by wrapping the articles even in a single sheet of tissue paper to avoid any reaction. Of course silk or other goods in merchantable bales are more fully protected.

4. As regards foods, as the odour of sulphur is only of short duration the point need not be discussed and I would point out that Mr. David, the chemist, distinctly states that there was no chemical change in the flour exposed and that none of the other food-stuffs suffered in their nutritious value. He further states that after the As to beef was exposed to the air for a short time it recovered its normal colour. cheese the discolouration was superficial and was confined to the exposed cut surface, In the vessels operated on the but there was no discoloration through the rind. ship's stores were left on board and exposed to the gas, and the report cited by me states that in no case was there any complaint from the ships or from the consignees of the cargoes.

It is true that vegetables such as potatoes and turnips did apparently absorb a certain quantity of acid, but when cooked it was found there was no trace perceptible either to taste or to litmus paper. When water and wine are exposed to the fumes in open bottles they do absorb the gas, which might very well be expected, It is stated but liquids in stoppered vessels or in barrels are not altered in any way. that wood painted pale pink becomes slightly darker. I have not experimented with pale pink, but colours ordinarily found on board vessels are unaffected. Steel, copper and nickel if well polished are tarnished superficially, but this tarnishing disappears on re-polishing with the ordinary plate-polish which is generally employed for keeping these things bright, and a very slight coating of a paste made of common whitening and water and allowed to dry previous to the introduction of the gas protects the metal.

5. With reference to inefficacy in the destruction of all the rats on board ship the experience in Dunkirk is that in proportion as the trial stage disappears the ships are cleared of all insects or rodents. In the last thirteen ships mentioned in Dr. Duriau's second report, eight were found to have had all their insects and rodents destroyed, while in five there remained only some nests of tiny rats. Since then some sixteen more ships have been disinfected and with the increased experience nothing has been found alive. In this connection the practical precautions which I mention in my report are important.

6. It will thus be seen that if the operations in France are examined further than the Proust-Faivre report referred to by the Local Government Board, the Clayton process has proved efficacious in destroying rats and other vermin, and is wholly without injurious effect on any important article of merchandise, with the exception of fruit.

*

8. I shall be glad if my memorandum is printed for communication to the Colonies, and, if it is thought advisable, this letter might also be added.

I have, &c.,

W. J. SIMPSON, M.D., F.R.C.P.

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IV.

Interim Report on Observation of the Clayton Sulphur- dioxide Process of Disinfection as applied in Destruction of Rats on Shipboard; by Dr. J. S. Haldane, F.R.S.

WH. POWER,

Medical Officer,

18th February, 1904.

By the courtesy of the Directors of the Anchor Line (Henderson Brothers) I travelled to Dunkirk, on October 6th, 1903, on the s.s. Bavaria, 3,009 tons register, to witness the disinfection of the vessel by the Clayton process, which is now employed at that port. The Bavaria, which is a cargo boat with accom- modation for only a few saloon passengers, had arrived in London a few days previously from Calcutta with a cargo partly for London and Glasgow, but chiefly for Dunkirk. The cargo for Dunkirk and Glasgow, submitted to dis-

infection, was as follows :—

For Dunkirk :

11,186 bales jute,

2,730 bags poppy seed,

9,941 linseed,

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2,226 grain (pulse).

For Glasgow:

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1,091 bags pulse,

1,092 wheat,

1,092

11 peas,

1 box cheroots,

1 case wearing apparel,

1 package cigars.

The vessel arrived at Dunkirk about 11.30 a.m. on October 7th, and was stopped for medical inspection and disinfection at a special berth.

A barge containing the Clayton apparatus was brought alongside immediately after the visit of the Port Sanitary Officials and the process of disinfection was com- menced about 1.30. The Clayton apparatus consists of an iron furnace specially constructed to burn sulphur. Air is drawn through this by means of a Root's blower, the products of combustion being cooled by passing them through a cooling apparatus below the furnace before they reach the blower. They are driven onwards through a flexible rubber hose which can be introduced into any part of the ship. A return pipe brings air back from the ship to the furnace. gas consists of the residual nitrogen of the air, together with about 15 per cent. of sulphurous acid, and a good deal of sulphuric acid in suspension. The presence of the latter makes the mixture white and opaque. It is a good deal heavier than air. The apparatus used was of a small size, and the hose was of only 34-inch diameter. Mr. Evans, of the Clayton Company, who was present at the operation, informed me that about 36,000 cubic feet per hour of gas were being delivered.

The

The men's quarters in the forecastle, together with the two small store. rooms below, in front of the collision bulkhead, were first treated, the hose being introduced through the door and down into the store-rooms. The operation was completed in about half an hour. The whole space appeared to