Infections of the Ovum, Embryo and Fetus 531 



is perfectly well known that the B. abortus is a permanent 

 resident of the mammary gland. It is not known that it is 

 not a permanent dweller in other parts, once introduced. 

 Although experimentally it has not been shown clearly that 

 B. abortus does or can invade the pregnant cow and cause 

 abortion there is good evidence that it is a dangerous infec- 

 tion in the genital tracts of cattle and that in the present 

 state of our knowledge attempts to use it as a therapeutic 

 agent are little short of criminal. Researches may throw a 

 more favorable light upon vaccination, but until they do the 

 prudent veterinarian and dairyman should leave this work 

 where it belongs — in the hands of experimenters. 



Upon the theory that the observed expulsion of a fetal 

 cadaver is a specific contagious disease, it is repeatedly pro- 

 posed to control abortion by quarantine restrictions asso- 

 ciated with disinfection of the aborter and of the premises 

 occupied by her. Public funds are expended in researches 

 upon "contagious abortion," and the public demands a visi- 

 ble return upon the investment. As a consequence the 

 United States Department of Agriculture, through its Bu- 

 reau of Animal Industry, and the agricultural experiment 

 stations of the various states are expected to advise dairy- 

 men and breeders how to control losses from "contagious 

 abortion." Not only do laymen who are suffering economic 

 losses demand a remedy, but they expect measures which 

 the ordinary dairyman or breeder can successfully apply. 

 The result is that much advice is given without visible bene- 

 fit. The owner is advised to quarantine all aborters, but 

 probably he sees less than one out of three fetal cadavers 

 which are expelled. Yet inferentially he is taught to believe 

 that those which he does not see do not matter and that 

 quarantining the known aborters will eliminate the danger 

 from the far greater number of unseen expulsions of fetal 

 cadavers. The abortion is not the disease. Once the fetal 

 cadaver and its membranes are expelled, that danger ends. 

 The cause of the expulsion of the dead fetus, the metritis 

 and cervicitis, continues indefinitely and quarantine does 

 not affect it in the least. Precisely the same infections 



