Page:Popular Science Monthly Volume 26.djvu/659

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URING the latter part of 1883 and the early part of 1884, I constructed at the Dogs' Home, Battersea, at the request of the committee of that institution, a lethal chamber for the painless extinction of the life of the animals which have, of necessity, to be destroyed there. I put the process first into operation on Monday, May 15th, by subjecting thirty-eight dogs to the fatal narcotic vapor. They all passed quickly into sleep, and from sleep into death. Since that time, for a period of seven months, the lethal chamber has been regularly in use. From two hundred to two hundred and fifty dogs per week have been painlessly killed in it, or a total of nearly seven thousand.

The thought of applying the anæsthetic method to the painless destruction of the lives of the lower animals, and the first accomplishment of it, came from myself, and dates back as far as the year 1850. In that year, I constructed at Mortlake, where I was then starting in practice, a small lethal chamber, to which my neighbors would frequently bring animals which they wished to have killed. In 1854 I began to illustrate this mode of painless death, and from that time up to 1871 I never allowed the subject to rest. In 1871 I brought it formally before the Medical Society of London. About this same time I made a communication to the Royal Society for the Prevention of Cruelty to Animals, and suggested a mode for killing painlessly dogs and cats that were wounded in the streets. From that time I have continued the inquiry, making use of all the known anæsthetic substances, in order to ascertain which was cheapest, most adaptable, most certain in action. The information thus obtained proved very useful when the time came for utilizing it.

In undertaking the practical act of carrying out lethal death on the large scale required at the Home, I had to determine, in the first place, on the anæsthetic or anæsthetics to be used; and, in the second place, to construct the room or chamber in which the animals should be confined while exposed to the lethal gas or vapor. I have placed on the wall a table of anæsthetics, including most that have up to this time been discovered, with a general outline of their respective properties and values. There is, you see, a goodly list, twenty-two in all. Out of these I selected, as shown by experiment to be the best, four: Carbonic oxide, chloroform, carbon bisulphide, coal-gas.

Carbonic Oxide.—I was led to carbonic oxide, not only by reading of it, and by witnessing the effects of it as a poison when it has been breathed from coke-fumes, but specially from studying its action when