94 SPECIAL CATTLE THERAPY 



(ate to begin preparations for delivering the calf at 

 once when this symptom is present, and in every case 

 I find a putrid fetus. This sign is doubly valuable as 

 an aid to diagnosis of these cases because, usually, a 

 putrid fetus is retained ; only rarely is a putrid fetus 

 expelled spontaneously at the end of the period of 

 gestation. All practitioners recognize the gravity of 

 this condition. 



It must, of course, be understood that this diagnostic 

 sign is in reference to those cases in which the fetus 

 dies and begins to degenerate while the os is still 

 closed. It would be of no value and has no bearing 

 on cases of fetal death resulting at the close of the 

 gestation period from dystocia. 



RABIES 



Eabies is not a common disease of dairy cattle. 

 When it does occur the diagnosis is made with little 

 difficulty ordinarily ; because a good history of the 

 manner of infection, almost without exception a dog 

 bite, can usually be obtained. 



The period of incubation in this disease is quite 

 variable, depending upon the amount of virus that has 

 been deposited, the virulency of the virus, the resist- 

 ance of the patient, and the location of the wound. 

 The period of incubation is shortest, other things be- 

 ing equal, when the bite is inflicted on the head ; ani- 

 mals bitten on the extremities take a longer time to 

 develop the symptoms of the disease. Probably in no 

 case, however, does the period of incubation exceed 

 three months; belief is no longer held in excessively 

 long periods of incubation in this disease. Now that 

 the infective organism has been recognized we may 

 expect positive data on this point in the near future. 



