Infections of the Ovum, Embryo and Fetus 535 



specific disease due to B. abortus, there are ample reasons 

 for believing that the blood of animals free from the infec- 

 tion of B. abortus does not react at all to these tests at the 

 lowest point where they can be applied. It is further evi- 

 dent that the tests fail at high dilutions when the infection 

 is abundant. This defect is well illustrated in Fig. 176, in 

 which the agglutination test was negative upon the day of 

 abortion. Two prominent advocates of the serologic tests 

 for the control of abortion, jointly published a bulletin in 

 1918 in which they said: "The serological tests are an im- 

 portant aid in the inauguration of preventive measures 

 against the spread of infectious abortion." Throughout the 

 publication, the serologic tests appear as the corner stone 

 in control measures. They advised the test as a means for 

 isolating the infected from the non-infected animals and for 

 preventing the introduction of the infection in purchased 

 cattle of both sexes. In 1919 they had modified their views 

 and in a second bulletin advocated the disinfection of the 

 copulatory organs of the bull as the most important meas- 

 ure of control available, and say: "Our work of the 

 past five years has convinced us that transmission by 

 the male is by far the most important means of spread- 

 ing the disease Proper disinfection of the 



sheath, therefore, constitutes the most, if not the only, im- 

 portant safeguard against the spread of infectious abor- 

 tion." The italics are mine. They present no data to 

 show that they accomplished any actual improvement either 

 under the repudiated first plan or under the second recom- 

 mendation. 



Another important group of believers that abortion is a 

 specific contagious disease advocate the quarantine of abor- 

 ters, plus the disinfection of aborting cows, of the external 

 genitalia of breeding bulls, and of the premises occupied by 

 aborters. There appeared an undated circular from one of 

 these sources with a title page printed chiefly in red which 

 reads in part, "Fight Contagious Abortion in Cattle 

 . . . Preventable — Controllable . . . Isolate af- 

 fected animals — Treat aborting cows — Disinfect bulls — 



