118 BOVINE PATHOLOGY. 



is termed its latent period. It varies mucli in different 

 diseases, and while it lasts the poison is undergoing 

 elaboration and multiplication in the blood. We may find 

 this latent period very prolonged in hereditary scrofula 

 or cancer, and by attention to avoidance of all exciting 

 causes it may be extended through even a long life. 

 The lesions of specific disorders are special, and therefore 

 pathognomonic, but they are not always present. The virus 

 introduced into the blood multiplies more or less readily, 

 according to its nature. It has to oppose the efforts of 

 nature for its excretion as well as, in some cases, to 

 struggle for existence with certain constituents of the 

 blood. If the resistance be too powerful the poison may 

 be thrown off before the end of the incubatory stage, or it 

 may persist until the febrile stage ; but not until it has 

 produced local effects. Ordinarily it acts locally, but 

 sometimes, especially in young and debilitated stock it 

 may increase in the blood so rapidly as to cause the fever 

 to run very high and destroy the animal before lesions 

 appear. We shall enlarge upon and illustrate these 

 points hereafter. In such cases as I have last described 

 no lesions are detectable after death except such as result 

 from the febrile state of the blood and the conditions of 

 that tissue itself. It is very dark in colour as a rule, and 

 petechias and also more extensive blood extravasations in the 

 various tissues occur, especially on the serous and mucous 

 membranes. Specific organisms may be detectable in the 

 blood when examined under a high power of the micro- 

 scope. 



Treatment of these disorders comprises prophylactic 

 measures, including sanitary port and county inspection — 

 measures of isolation, such as quarantine ; thorough dis- 

 infection of all infected places and things. Such imply 

 Government as well as private enterprise. This is ab- 

 solutely essential, as has been proved by many a national 

 loss incurred, and a few such disasters prevented. The 

 public must learn that remedies must be proportioned to 

 diseases. Sporadic cases are of individual interest, and 

 must be attended to by individuals ; enzootics require 



