The pathological changes found after death from hydrophobia are not characteristic. Tho most constant. are found in the nervous system, especially in the region of the medulla oblongata and puns. The changes consist in a varying de gree of inflammation, marked by small round cell infiltration of the blood-vessel walls, exuda tion into the perieellular lymph-spaces, small hemorrhages. and sometimes thrombosis of the small blood-vessels. More recently extensive degenerative changes in the nerve-cells have been described. Lesions have also been noted in the sympathetic, consisting in degeneration of the nerve-cells and increase in the thickness of their endothelial capsules. In addition to the changes in the nervous system. there is usually congestion of the mucous membrane of the gastrointestinal tract and of the pharynx, larynx. and bronchi. Despite the fact that innumerable attempts to discover the cause of the disease have been made without success, it still seems probable that hydrophobia is due to a micro-organism. This organism is not apparently widely distributed throughout the body. but confined mainly to the saliva and the central nervous system. An emul sion made of the medulla of a rabid animal, injected into dogs, eats, rabbits, guinea-pigs, etc.,' produces symptoms characteristic of the disease, although in rodents there is little or none of the stage of excitement. • Although we have no knowledge as to the spe cific germ of the disease, hydrophobia furnishes our most remarkable example of the success of artificial immunization by means of protective inoculation. To the French student Pasteur (q.v.) is due the credit not only of the discovery of the preventive treatment of hydrophobia, but of demonstrating, through it a principle in thera peutics which is of constantly widening applica tion. Pasteur found that lie could induce the disease in rabbits by inoculations with portions of the spinal cords of rabid animals, and that the spinal cords of these rabbits possessed a high degree of virulence. Drying in air reduced the virulence in direct proportion to the length of the drying. It was found that, while inoculation of man or animals from the fresh rabbit-cords was invariably fatal, if the man or animal was first inoculated from one of the cords the virulence of which had been greatly reduced by the drying, and then from cords of gradually in creasing virulence, he could become so accus tomed to the virus that injection of the fresh cord would no longer be fatal, and such a series of inoculations made sufficiently soon after the bite of a rabid animal was found to prevent en tirely the development of the hydrophobia. Ad vantage is taken of the long period usually elapsing between the bite and the onset of the disease to practice these preventive inoculations, and the result has been a marked decrease in the mortality from the bites of rabid animals. In tiew of the uniformly fatal results of hydro phobia and the success of the Pasteur treatment, the importance of determining, at the earliest possible moment whether the animal by whom a person has been bitten had rabies can be read ily appreciated. The animal should not lie killed,
for as rabies is invariably fatal to canines, the recovery of a sick animal definitely disproves rabies. on the contrary, the animal should be carefully watched, and if it dies, should he sent to a laboratory where examination can be made and the question of rabies definitely settled by inoculation experiments on animals. The treat ment should he cauterization in every case, less than one hour after the bite, by means of the actual cautery, strong acid, or acid nitrate of mercury. Wounds must be opened by the sur geon. and even amputation may be necessary. Washing, and syringing wounds with water at 130° F. is desirable. Sucking the wound to draw out the poison has been practiced, and may be safely done if there are no breaks of the mem brane of the lips or mouth. Administration of morphine or alcohol does harm. Immunizing by the Pasteur method should be practiced in all cases. By this method the patient is inoculated with attenuated virus by the injection hypo dermically of emulsion made from the brain of a rabid animal. repeated in stronger and stronger concentration during twenty-one days. The re sults of the Pasteur method are now indisputable, hut it is of the utmost importance lo begin the treatment as soon as possible niter the injury, as the prospect of success grows less and less day by day of delay. Folimaiog are the results of the antirabie treatment at the 'Institut Pas _tour, Paris. from ISSfi through 1S99: cases were treated. with 99 deaths; showing a mortality of 0.45+ per cent. In 1900 there were thirty•tive Pasteur institntes in the world. at the following plhces: Eight in Frame, six in Russia, five in Italy, two in Austria, in New York City, one in one in Baltimore, one in Havana, one in Bit) Janeiro. one in Buenos Ayres, one in Saragossa, one iu „Malta, out' in in Constantinople, one in Aleppo, one in Tiflis, one in Algiers, and one in Athens.
PsKunottAnws, or LvssoenomA, is a neuras thenic or hysterical condition. in which the patient. who imagines that he has rabies, in his morbid condition of mind enacts sonic of the symptoms. and may even be frightened to death. Consult: Yonalt. tht Or nine Madness (London. 18:111) ; Suzor, Hydrophobia: in Account of M. Symtem ( London, 1SS7); Babes, in moues de rinstittit Postuur, vol. V. (Paris, IS92) Byron. Researches in the Loomis Labora tory (New York, IS90) ; Pasteur, in rendus de r.teath'inic des Sciences (Paris, ISSI and IsS9), and in .Innales de l'Institut Pasteur ( Paris, ISS7.SS ) Salmon. "Development of Knowledge Concerning Animal Diseases," in U. S, Department of Agriculture, Bureau of Animal Industry, uth Annual Report (Washington, 1s99).