VACCINE-THERAPY 121 



lating the other excretory organs — i.e., the bowels and skin. 

 The subcutaneous or intravenous injection of normal saline 

 solution assists the system also in the removal of an ever- 

 accumulating effete deposit. 



Endometritis. 



Bacterial invasions of the womb in the lower animals are 

 of rather common occurrence, due largely to contamination 

 at the time of delivery on the part of unskilled attendants, 

 and also by the retention of the placenta. 



One also sees many cases following upon difficult par- 

 turition, through injuries caused to the mucosa either by 

 the foetus itself during the process of delivery, the acci- 

 dental slipping of instruments, and, above all, the want of 

 complete asepsis on the part of the operator. 



Some species of animals are more tolerant to the patho- 

 genic influences of bacteria growing in the generative 

 female organ than others. The cow, for example, is prob- 

 ably the most tolerant of all the domestic animals, while 

 the mare is the least. 



Why this is so is somewhat difficult to explain, but it is 

 more than probable, in the light of our present know- 

 ledge, that those animals which are most resistant are 

 endowed by Nature with the greatest supply of bacterio- 

 tropic elements. It is a well-known fact that the uterine 

 fluids at the time of and after parturition possess powerful 

 bacteria-destroying properties, and it may be due to those 

 strong bactericidal qualities also, the possession of which 

 is greater in some species of animals than in others, that 

 we see in practice such variable degrees of resistance 

 versus susceptibility. 



As already pointed out, uterine bacterial invasion in 

 practice takes place incidentally to parturition in some 

 form or another, and, indeed, it would seem almost a 

 physical impossibility for the womb to become invaded in 

 animals at any other period, for during a process of 

 quiescence of that organ it is hermetically sealed, and it 



