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PUBLIC RECORD OFFICE

Reference :-

C.O. 885

PUBLIC RECORD OFFICE, LONDON

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

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disease, it is valuable to the merchant, whose losses by rat damage must frequently be considerable. It is estimated that separately from the damage that it causes, every rat on board ship eats at least a pennyworth of food per day, which, on a long voyage and a rat-infested ship, must total up to a considerable amount by the time the voyage is over,

The fact that the gas has no injurious effect on silks and flannelettes of varied colours, except in the case of the blue silk which was changed, to a slightly lighter shade, removes the objection which merchants and others very reasonably raise to fumigations in general.

17. French experiments with the gas show it has no injurious effect on mer-

Manora." chandise, and are confirmatory of the experiments made on the S.S." In France dyed silks of more than 150 colours were exposed to the gas by Professor A. Rosenstiehl, of Paris, and only three were found to be sensitive, having their colours modified in shade, but not faded or deadened.

In March, 1903, Dr. Gustave Duriau, Director of the Sanitary Service at Dunkerque, reports that a bale was made up of the following stuffs:-

(1) 25 samples of stuffs of silk of all shades, from the palest to the darkest,

plain, figured, printed, woven.

(2) 25 samples of woollen stuffs, plaids of all colours.

(3) 112 samples of cotton stuffs, indienne, printed matter, all colours.

(4) 20 samples of variegated woollen stuffs, woollen plush, polonaise, flannel,

veiling, belting, cashmere, all colours.

(5) 111 samples of cotton stuffs, tickings, of all colours.

(6) 7 samples of woven velvets, printed goods, velvets, miroir embossed, and

plush of all colours.

(7) 38 samples of plain cloths of all colours.

In all 338 samples of stuffs, representing nearly all the specimens which would be imported by vessels. In each of the seven series litmus paper was interlaid, then the seven series were reunited in a bale and sewn in canvas similar to that used in practice.

On Wednesday, 18th February, 1903, on board of the steamer "MacDonald,” coming from Bombay, the bale was lowered, attached to a cord through the ventilator right to the bottom of hold 3. It was by this ventilator that the discharge of sulphurous gas was made. The sulphuration of this hold lasted 24 hours, and the percentage during the operation was from 7 per cent. to 12 per cent.

Owing to the forgetfulness of a guard, the cord was allowed to be detached, and the bale could not be taken out until the unloading of this hold was accomplished, that is to say, Tuesday, the 24th of February, 1903.

The bale thus remained:-

1st.-During 24 hours in contact with the sulphurous gas sent under pressure

from the Clayton furnace.

2nd. During a length of time, difficult to determine, in contact with these vapours, until the complete evaporation of the sulphurous gas, which usually remains quite a long time at the bottom of the hold.

3rd. During six days it was exposed to the atmospheric variations, the hatches

being opened all day long for the discharge of this hold. The bale then remained in the condition similar to that in which it would have been, had it really been a part of the cargo of the ship.

Wednesday, the 25th February, it was opened in the presence of Mr. David, Chief Chemist of the Ministry of Finance, that is to say:-

1st.-All the litmus papers were reddened.

2nd.-The samples no longer smelled of sulphur.

3rd. Not a single one had been affected, the different shades were identified with those of the test samples which had been preserved during the entire time in a dry place.

As a result of this experiment we then can affirm:-

1st. That the sulphurous acid penetrated everywhere in the bale, litmus

paper reddened.

2nd.—That the sulphurous acid entirely evaporated, leaving no odour. 3rd. That the stuffs in bales, without being rapidly aired (six days in the

hold), are not at all affected, and show no discolouration whatever." Dr. Duriau concludes his report by stating that "the Clayton process appears

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to deserve to be adopted, as much from a scientific as from a commercial point of view, because it suffices for the destruction of rodents, insects and all kinds of microbes, without damage to goods, fittings, provisions, or machinery; and because the operation of disinfection is rapid and cheap."

18. Remarks on the practical application of the gas.-The secret of the success of the method and of no injurious effects being produced either on the texture or colour of the fabrics exposed to the action of the gas, appears to lie in the cooling of the gas before it is forced into the compartment to be fumigated: were it pumped in in a heated condition there would be condensation of the gas when it cooled, which would be then liable to damage some of the merchandise. In fumigating it is important that the compartments already fumigated should not be opened until those adjoining have been filled with the gas. This precaution is necessary to pre- vent the rats from escaping into compartments already fumigated. For the same reason it is also necessary to have no part of the ship unfumigated; even the boats should be exposed to the fumes. The duration of the fumigation should be adapted to the size of the ship. For small ships the gas, at a concentrated strength of 10 to 12 per cent, should be in the holds for fully six hours, while for the largest vessels and liners it should be for much longer, which need cause no great inconvenience, for if the fumigation is begun in the early morning the cabins will be fit for occupa- tion at night, while the holds will retain the gas.

19. Recommendations.-The experience of the last few years proves that plague has spread over different parts of the world in spite of existing precautions, and that the extension has not always been by a sick person. In most cases the first intimation of the disease having arrived in a new locality has been the mortality from plague among the rats. Any process, therefore, which will destroy the rats and insects on ships having commercial relations with plague-infected ports, and will at the same time destroy the infection of plague which may be on the ships, and accomplish these without any damage to the merchandise and cargo, is a weapon of the utmost value, when properly used, in combating the spread of plague.

There can be no doubt that the toxic gas generated by the Clayton apparatus

is such a weapon, and it is obvious that the general adoption of the Clayton apparatus and its proper use in infected ports, and also in those ports which have commercial relations with infected ports, will secure a greater degree of safety with less incon- venience, delay and expense than has been attained by the existing precautions or by quarantine. Ships, especially mail ships, would find it to their advantage to carry a disinfector with them, so that the rats could be destroyed and the cargo fumigated under the supervision of the medical officer before arriving in port. Ships carrying emigrants, coolies and soldiers, also cargoes of fodder, forage and grain would be less liable to transport disease if periodically subjected to the action of the gas.

In the case of transit ports, where only a small amount of cargo is discharged and other cargo is taken on, and it is impossible to clear the hold of the ship of all the rats which have been killed by the fumigation, it is sufficient to fill up the hold with gas and keep it there until the port of arrival is reached, to prevent the rats which have been killed from decomposing.

Nor is the use of the apparatus limited to maritime commerce; it would be found to be useful also on shore. One of the features of the spread of plague in South Africa and probably elsewhere has been the number of railway stations or stores in which plague rats have been discovered, the infection having been probably carried in the cargo by the trains. This could readily be avoided by having the warehouses disinfected with the gas, and the cargo from an infected centre fumigated at the place of departure, and, if need be, if the town is a large one such as Bloem- fontein, Kimberley, Johannesburg, Pretoria, Newcastle and Standerton, at the place of arrival. This could be easily done by one or more of Clayton's machines on a railway truck at important places such as these.

It is not only, however, in relation to the spread of plague from locality to locality that the apparatus is useful, but it will be equally useful in combating a plague outbreak in a locality, as it can be used for the destruction of rats and insects in the houses of an infected area, and at the same time as a disinfector of the houses, and the furniture and clothes in them. In this respect it is superior to other disinfectors, in that with its use there is no need to remove anything from the house

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