Researches on the Diseases of Animals.
BY PASTEUR AND OTHERS.
Pasteur's results may be summarized as follows: It is proved by inoculation experiments that both quiet and raving madness originate from the same poison. The symptoms of madness are extremely variable, and depend apparently on the part of the nervous system attacked by the poison. The infectious matter is in the form of microbes in the saliva of mad animals; inoculation with it causes death in three ways, either by microbating the saliva, or by the excessive production of pus, or by the development of madness. The marrow, brain, and spinal cord are always, virulent in all animals dying of madness, the virulence increasing until putrefaction sets in. In one case a brain was sustained at a temperature of 12° for three weeks by this action. To produce madness quickly and surely, after trepanning, inoculate in the skin on the surface of the brain; the disease will make its appearance in 6, 8, or 10 days. The malady produced by injection into the blood system exhibits symptoms which differ greatly from those of raving madness caused by a bite or by inoculation after trepanning, and hence many cases of the quiet form may escape observation. In those which may be termed moderate, pronounced paralysis ensues, whilst raving and howling are not observed. When the poison is injected into the blood, the spinal cord seems to be the first point attacked. Injection of saliva or blood from a mad subject into the veins does not protect a dog from a subsequent outbreak of madness, or from death after a second inoculation of mad matter, either by trepanning or injection in a vein. Cases of spontaneous recovery have been observed when early symptoms only were developed, but never after the symptoms became violent. In some cases after they had disappeared they returned after two months, whereupon death followed.
As a great many sheep are lost after protective inoculation for sheep-pock, Peuch has investigated the subject, and from the results of his experiments draws the conclusion that this danger may be greatly reduced by using small quantities of lymph diluted 60 to 120 times.
Thiernesse and Degive have made experiments on protective inoculation for lung epidemics. Their results show that 2 grams of lung epidemic poison may be injected into the veins without danger, provided it does not touch the cell-tissue. Immunity to the same extent results from this injection as from the tail inoculation recommended by Willems. Immunity in this case is sometimes perfect, and does not cause changes which occur when the disease is taken in the natural way.—Bid. Centr., 1883, pp. 674-677; Jour. Chem. Soc., May, 1884, p. 623.