304 AGRICULTURAL BACTERIOLOGY 



to,abort more than once or twice, and such condition is fre- 

 quently interpreted as an indication that a certain degree 

 of immunity has developed as a result of the earlier attack. 

 It seems probable that this is not the case, but that there is 

 an age immunity, since the greatest number of abortions 

 occur with heifers during the first and second pregnancies. 

 It is not good practice to sell aborting animals with the 

 hope of getting rid of the disease, since it will rarely if 

 ever succeed. The replenishing of the herd by purchase 

 will serve to continue the trouble, either by the addition 

 of healthy animals to become infected, or by the introduc- 

 tion of new centers of infection. 



Many treatments have b?en devised and recommended 

 for the prevention and cure of abortion. For example, the 

 internal administration of carbolic acid, both with the feed 

 and by hypodermic injection, has been widely used. There 

 is little reason to believe that it has any favorable effect. 

 The use of vaccines has been attempted, but without suc- 

 cess. It seems evident that the breeder and farmer must 

 rely entirely on sanitary precautions to prevent the spread 

 of the disease. He must seek to destroy the organism in 

 the infectious material discharged by the animal. The dead 

 fetus and also the afterbirth should be buried ; the contami- 

 nated litter should be clestro}^ed ; and the aborting animals 

 should be flushed out with a 0.5 per cent, solution of some 

 of the soapy, coal-tar disinfectants, such as lysol, or with a 

 0.5 per cent. Lugol's solution, which consists of one part of 

 iodine and two parts of potassium iodide dissolved in three 

 hundred parts of water. The solution should be warmed 

 to 100 F. The treatment should be continued daily until 

 no discharge is to be noted. This procedure will not only 

 serve to limit the distribution of the organism, but will be 

 of some service in the prevention of sterility, which is a 

 frequent sequence of abortion, and an important factor in 



