392 DISEASES OF CATTLE. 



and chiefly restricted to children and to those adults who handle sick 

 animals or drink large quantities of unboiled inilk. Some veterina- 

 rians regard the human affection as by no means uncommon in countries 

 where foot-and-mouth disease prevails, but that the disturbance of 

 health is usually too slight to come to the notice of the family doctor. 



The disease prevails in European countries and occasions great losses. 

 Although the actual mortality is quite low, and not more than 1 to 3 per 

 cent of the affected animals die, serious losses result from the diminu- 

 tion of the milk secretion and consequent interference with the busi- 

 ness of the dairy. There is likewise more or less loss of flesh in 

 animals. 



According to the very accurate statistics collected by the German 

 Empire, 431,235 head of cattle, 230,868 sheep and goats, and 153,808 

 swine were affected with the disease in that country in 1890. The 

 infection, quite insignificant in 1880, had been gradually spreading 

 until it reached the enormous figures given above in 1890. During 

 this same year it prevailed in France, Italy, Belgium, Austria-Hungary, 

 Switzerland, Koumania, and Bulgaria. 



Contrary to most other infectious diseases, foot-and-mouth disease 

 may attack the same animals repeatedly, provided the intervals between 

 the attacks are longer than six to twelve months. The immunity or 

 protection conferred is thus only of limited duration. Hence protective 

 inoculation with the virus, in whatever manner it may be practiced, is 

 not only of no use but decidedly dangerous, as it will introduce the 

 disease. It is, however, not uncommon in European countries to practice 

 inoculation after the disease has appeared in a herd in order to hasten 

 its progress. This is highly recommended by some, since it not only 

 hastens the infection, but the disease is apt to be milder and limited to 

 the mouth. It consists in nibbing with the finger or a piece of cloth a 

 little of the mucus from the mouth of a diseased animal upon the inner 

 surface of the upper lip of those to be inoculated. From 50 to 75 per cent 

 of the inoculated animals take the disease. 



As with other communicable diseases, the source and origin of foot- 

 and-mouth disease has given rise to much speculation. The disease had 

 been known in Europe for centuries, but it was not until a comparatively 

 recent date that the erroneous conceptions of its spontaneous origin as 

 a result of climatic and metorological conditions, exhausting journeys, 

 etc., were abandoned. It is now generally conceded that foot-and-mouth 

 disease is propagated by a specific virus and that every outbreak starts 

 from some preexisting outbreak. 



The infection is contained in the eruptions, and hence shed from the 

 mouth and the feet. A wide distribution of the virus and a rapid infec- 

 tion of a herd is the result. Animals may be infected directly by coming 

 in contact with the diseased, or they may be exposed to the virus in 

 stables, in the field and along roads, in cars, and in all places shortly 

 before frequented by diseased cattle. Human beings may carry the 



