Infections of the Ovum, Embryo and Fetus 521 



in the utero-chorionic space. Into this space it is not known 

 that any disinfectant borne in the blood ever enters. It 

 probably does not. Even should a disinfectant leave the 

 blood stream and enter the utero-chorionic space, it is in- 

 conceivable that sufficient would enter to disinfect. The en- 

 dometrium of a pregnant cow at full term represents ap- 

 proximately fifteen square feet of mucous membrane, op- 

 posed to which is the somewhat smaller surface of the con- 

 tiguous chorion. Between the two there exist, in badly in- 

 fected cows as revealed in the abattoir, from a few ounces 

 to several quarts of "abortion exudate." It must require 

 great confidence in the potency of disinfectants to believe 

 that a sufficient quantity can enter the utero-chorionic cavity 

 to disinfect it, or pass the placental filter and, after coursing 

 through the fetus, be poured into the fetal alimentary canal 

 and disinfect the meconium. The employment of disinfec- 

 tants in this apparently hopeless manner has been virtually 

 abandoned — permanently, it is to be hoped. 



The generally accepted theory that abortion in cattle is a 

 specific contagious disease led many of the subscribers to 

 that belief to hope for a specific remedy in the form of a 

 serum, bacterin, vaccine, or other biologic substance. Nota- 

 ble achievements in this field had been made in a number 

 of diseases of man and animals and it was assumed that in 

 abortion a similar victory was probable. 



The achievements in the biologic control of disease have 

 been chiefly among those maladies designated as acute, in 

 which a definite immunity follows the recovery of the pa- 

 tient. In chronic infections little progress has been made 

 in biologic therapy, apparently because the success of these 

 products is dependent upon their power to produce that 

 state known as immunity. Infectious diseases are divisible 

 primarily into acute and chronic. In acute infectious dis- 

 eases the infection and the patient can not long coexist. 

 Either the infection kills the patient or there develops with- 

 in the body of the patient substances which destroy the 

 infection and which thereafter prevent, for a variable pe- 

 riod, re-infection. This is known as immunity. In chronic 



