CHEONIC INFECTIOUS DISEASES 111 



commended by McFadyean and Stockman for the 

 once almost universally accepted specific infection by 

 B. abortus has been extensively employed in this 

 country. The procedure of immunisation is as follows : 

 50 c.c. of a living virulent bouillon culture of the 

 B.ahortnssiYe injected subcutaneously six to eight weeks 

 before the animal is put to breed. After injection the 

 animal shows depression, loss of appetite, and a decrease 

 in milk supply; there is also swelling and tenderness 

 over the seat of injection. These symptoms continue 

 for about twenty-four hours, when the animal may 

 regain the normal, or the tenderness at the seat of 

 injection may continue and an abscess form ; this latter 

 sequel is quite common. Immunisation by the above 

 method is now falling into disuse in many countries 

 where it had been extensively employed, for the reason 

 that it is now considered a great means of continuing 

 the infection, and disseminating it to healthy animals. 

 Infectious abortion of mares is caused by a strepto- 

 coccus, the B. abortus equinus. No work is recorded 

 relative to immunisation to this disease. 



Infectious Vaginal Catarrh of Cows, or Granu- 

 lar Venereal Disease. — Infectious vaginitis is a 

 chronic infectious disease of cattle which is princi- 

 pally characterised by peculiar nodule formations on 

 the vaginal and vulvar mucous membrane. 



Etiology. — A Gram-negative streptococcus is con- 

 sidered to be the cause. This disease is found very 

 frequently among cows ; infection is spread very 



