The most efficient method of getting rid of this pest of the Army biscuit is a complete and thorough fumigation of the infested premises with carbon bisulphide. But, as this substance is not only poisonous but inflammable, it is well to get a chemist to undertake the proceeding, and also to notify the Insurance Company. Fumigation by sulphur ruins the flour. Another remedial measure is that of turning the steam from the boilers on to all the infected machinery and walls.
That this destruction of the Army biscuit is a matter of considerable importance is shown by the fact that biscuit-rations exported to the colonies in hermetically sealed tins have become quite unfit for consumption, and this destruction has been noted in places as far distant from each other as Gibraltar, the Sudan, Mauritius, Ceylon, South Africa, and Malta. That it is also an old trouble is shown by the following quotation from the diary which Sergeant Daniel Nicol, of the 92nd (the Gordon Highlanders), kept during the expedition to Egypt in 1801:—
Some vessels were dispatched to Macri Bay for bullocks, and others to Smyrna and Aleppo for bread which was furnished us by the Turks—a kind of hard dry husk. We were glad to get this, as we were then put on full rations, and our biscuits were bad and full of worms; many of our men could only eat them in the dark.[7]
With regard to the actual baking of the biscuit, Colonel Beveridge and Mr. Durrant suggest that the temperature conditions during the process of cooling should be made as unfavourable as possible for the moths by introducing screened cool air, which can be forced in at one end of the cooling-chamber and sucked out at the other. Could such a scheme be adopted it would be difficult, if not impossible, for the moths to lay their eggs, and the biscuit would thus be more rapidly cooled. In any case it should not be difficult to ensure that the cooling takes place in some chambers which are practically free from these destructive moths.
CHAPTER V
FLIES
Part I
THE HOUSE-FLY (Musca domestica)
Musca est meus pater, nil potest clam illum haberi;
Nec sacrum nec tam profanum quidquam est, quin Ibi ilico adsit.