504 Veterinary Obstetrics 



observe that sometimes in young cows and mares there occQrs a 

 swelling of the vulva and a discharge of mucus, along with some 

 slight symptoms of general disturbance, which later disappear, 

 and the animal completes the period of gestation and gives birth 

 to vigorous, living young. 



Some investigators hold that a microscopic examination of the 

 discharges from the vagina, aiid the indentification therein of the 

 abortion bacillus, constitutes one of the most rapid and reliable 

 methods for diagnosing the disease. 



It would appear, however, that, while the symptoms recorded 

 above are all valuable in aiding the veterinarian to reach a con- 

 clusion, until the disease is much better known than at present, 

 it is safer to regard any case of abortion in a dairy as suspicious 

 of being due ta infection and to treat it as such, especially if 

 that malady already exists in the vicinity or if a new animal has 

 been introduced into the herd, which might carry with it the 

 infection. 



Infectious abortion is to be carefully differentiated from the 

 granular venereal disease, which, although causing abortion in 

 50 to 70 % of the pregnant cows attacked, is nevertheless a quite 

 distinct malady and offers a different problem in handling. 



Since our account of this disease on page 97 has come from 

 the press, the malady has been definitely recognized in Northern 

 New York and is possibly extensively distributed in America. 

 Its recognized existence in America demands that it should 

 receive more extensive consideration at our hands. This we 

 shall accord to it in an appendix. 



The course of abortion in a stable or herd is very much like 

 that of any other infectious disease. Upon its first appearance 

 it usually assumes a highly virulent character and for a time 

 may increase in virulence, to later slowly and gradually abate 

 as if it had consumed the fuel upon which it might feed. 

 Finally the disease gradually disappears, unless new material is 

 constantly provided by the introduction of new cows which have 

 not previously beeu exposed to the malady. Investigators of the 

 disease usually claim that a cow will abort two or three times 

 from the infectious disease and, after such a period, usually ceases 

 to abort and again breeds. A large proportion of the cows which 

 abort two or three times, however, are sold and thus disappear 



