INFECTIOUS DISEASES OP CATTLE. 399 



of milch cows have become affected, and instances are reported in 

 which sloughing of the tegument immediately around the ulcer upon 

 the udder has occurred. Owing to the tough, fibrous nature of the 

 bovine skin, it is exceeding rare for sloughing to occur upon any part 

 of the body other than those mentioned. 



The attack upon the feet of an animal is frequently manifested in 

 all four feet at once, but one or more of the feet may entirel\ escape 

 and remain unaffected throughout the course of the disease. As the 

 feet Ijecome sensitive and sore the animal lies down jDersistently. and 

 it has been found that bed sores develop with amazing rapidity in all 

 such cases and wholly baffle all attempts at treatment until after the 

 patient has regained its feet. 



The disease may attack some of the internal organs before it 

 appears upon any of the external tissues. These cases are very liable 

 to prove quickly fatal. The animal dies from paralysis of the heart 

 due to the formation of poisonous principles within the system, or it 

 may suffocate by reason of the action of these same poisons upon the 

 tissues of the lungs, or it may choke to death as a result of paralysis 

 of the throat. 



In cases of serious affection of the udder the erosions will often be 

 found located within the passages of the teats, resulting in a " caked " 

 udder, and the same toxic poisoning, which is the cause of death in 

 the apoplectiform types just mentioned, may arise from this source. 

 In any event the uiilk from such cases will be found dangerous for 

 use, causing fatal diarrhea in sucking calves or young pigs and 

 serious illness in human consumers. The milk obtained from cows 

 suffering with foot-and-mouth disease is not readily converted into 

 either butter or cheese, but remains thick, slimy, and inert in spite of 

 churning and attempts at curdling. The ulceration of the interdigital 

 tissue may extend to the ligaments of the fetlock or produce disease 

 of the joint or bone. Pregnant animals may abort. In pigs, sheep, 

 and goats the lesions in the foot are most common, but both forms 

 may be observed or only the mouth lesions. 



When the disease has become fully established it will be found that 

 the duration of the attack will vary greatly with different animals. 

 From 10 to 20 days are usually required for the recovery of the 

 normal appetite and spirits in mild outbreaks, while the return to a 

 full flow of milk, in the case of milch cows, is seldom witnessed before 

 the arrival of the following season. 



In the malignant type of the disease it requires from three months 

 to a year for an animal to recover. The "mortality is not great, gen- 

 erally about 1 to 3 per cent, but in severe outbreaks it may reach 5 

 per cent. It is more fatal in young animals that have been fed on 

 infected milk, and produces death in from 60 to 80 per cent of these 

 cases as a result of gastro-enteritis. 



