FOOT-AND-MOUTH DISEASE 445 



already in the early stage of the disease. Immune serum, if properly 

 preserved, retains its protective and curative properties for several 

 years ; in one observation for five years. 



AFRICAN HORSE SICKNESS. 



This affection, also known as pestis equorum, "Pferdepest" 

 (German), peste du cheval (French), is an acute or subacute disease 

 of horses, prevalent in epizootic form in Africa. As first demonstrated 

 by McFadyean and afterward by Nocard, it is due to an ultra- 

 microscopic, filterable virus. Theiler, Eddington, and Koch have 

 studied the disease, with the object of preparing a protective serum. 

 The most important pathologic changes of the disease are gelatinous 

 infiltrations of the subcutaneous and intermuscular connective tissue, 

 swelling of the superficial lymph glands, very marked catarrhal 

 swelling of the mucosa of the stomach, and the first portion of the 

 small intestine, edema of the lungs, and occasionally the formation 

 of gelatinous deposits on the pleura, pericardium, and epicardium. 

 One attack of the disease produces a relative immunity only, and 

 animals which have recovered from the disease may again be made 

 very sick by the injection of large doses of virulent blood. Koch used 

 horses which had passed through a natural infection (so-called "salted" 

 horses) in the preparation of an immune serum of high value. It is 

 obtained by injecting into "salted" horses increasing doses of virulent 

 blood obtained from sick horses shortly before death. According to 

 Theiler the protective inoculation consists in the injection of 300 c.c. 

 immune serum into the jugular vein and of a small amount of virulent 

 blood under the skin. 



FOOT-AND-MOUTH DISEASE. 



Foot-and-mouth disease, also known as aphthae epizooticse, 

 aphthous fever, infectious aphtha, eczema epizootica, "Maul und 

 Klauenseuche" (German), "fievre aphtheuse" (French), is an acute 

 highly contagious fever, due to a specific contagium. It is character- 

 ized by the eruption of vesicles or blisters in the buccal mucosa, 

 around the coronets of the feet, and between the toes. It is most 

 commonly a disease of cattle, but it also affects swine, sheep, goats, 

 buffalo, bison, deer, etc., and less frequently horses, dogs, and cats. 

 Man may be infected by contact with sick animals or by drinking 

 their raw milk. 



The contagium, an ultramicroscopic filterable virus, is contained in 

 the contents of the vesicles, in the saliva and milk, and during the 

 height of the disease, also in the blood serum. While the mortality 

 from the disease is generally not very high, epidemics are so wide- 



