Page:Popular Science Monthly Volume 46.djvu/533

 The horses selected for the purpose of supplying serum should, Roux states, be ordinary coach horses from six to nine years old, well nourished but incapacitated for work on account of some injury of the limbs. Such horses must be carefully examined to determine the absence of lesions of the internal organs, especially of the kidneys, while the absence of tuberculosis or glanders must invariably be determined by a failure of the animal to react to an injection of tuberculin or mallein. Roux reported the details of the process in a horse seven years old, weighing four hundred kilogrammes, that was injected beneath the skin of the neck or behind the shoulder with toxine, one tenth of a cubic centimetre of which sufficed to kill a guinea pig weighing five hundred grammes in forty-eight hours.

In two months and twenty days this horse received more than eight hundred cubic centimetres, or twenty-five ounces, of toxine with no worse symptoms than transient local swelling and temporary rise of temperature about one degree centigrade. Serum was obtained from this horse by bleeding it on the eighty-seventh day, and immediately thereafter two hundred cubic centimetres of toxine were injected into the vein with but moderate subsequent fever. The latter procedure is less efficacious than injecting smaller doses of toxine from time to time and allowing the animal to rest for twenty days before being bled again. Roux has horses from which blood has been taken more than twenty times with a large trocar, yet the vein is as supple as in the beginning.

The serum obtained from the horse above referred to had a preventive power above fifty thousand—that is to say, a guinea