Annual Report for l'^12 of Royal Veterinary College. 275 



also allowing that the one case out of 535 presumably healthy 

 animals in which the test had a positive result was also a 

 failure or error of the test, it is perfectly clear that this means 

 of diagnosis is calculated to render very great service in dealing 

 with contagious abortion. 



It must be observed, however, that it is not at all certain 

 that the test was at fault in the one case in which serum from 

 a presumably healthy animal gave a positive result, because it 

 must not be assumed without strong evidence that infection 

 with the abortion bacillus is confined to cows or to pregnant 

 animals. With a view to clearing up this point a considerable 

 number of experiments (of which details will subsequently be 

 published) have already been made, and the results have been 

 rather surprising, inasmuch as it has been found easy to infect 

 bovine animals of both sexes and of various ages with the 

 abortion bacillus. Infection has been obtained in both sexes by 

 giving a small quantity of artificial culture by the mouth, and 

 it has been produced in bulls and steers by injecting the bacilli 

 into the sheath. In these experiments the blood was tested at 

 intervals after the attempt to infect, and it was assumed that 

 infection had actually taken place when the agglutination test 

 gave a positive result. 



The experiments and observations which have already been 

 made appear to justify the statement that in dealing with 

 outbreaks of abortion the agglutination test will enable one 

 to say with almost absolute certainty whether the disease is of 

 the contagious kind or not. The value of the test is greatly 

 enhanced by the fact that it is not merely a reliable means of 

 diagnosis after abortion has actually occurred, but can be 

 successfully employed for diagnosis in animals that are still 

 carrying their calves. 



When the first case of abortion occurs in a herd the proper 

 procedure therefore now is to have the animal's blood tested 

 immediately, and in the event of the result of the test being 

 positive this should be followed up by testing the blood of all 

 the other animals in the herd, so as to detect those in which 

 infection has ali*eady taken place. 



During the past year this system has already been adopted 

 in a number of herds, and so far the method promises to have 

 very successful results. The experiments are being continued, 

 and members of the Society who have, or who suspect that they 

 have, contagious abortion in their herds are invited to apply for 

 assistance in diagnosis to the Royal Veterinary College. 



John McFadyean. 



Royal Veterinary College, 



London, N.W. 



