iv Preface 



The pathologic processes occurring in the genitalia of 

 animals have been almost wholly described under the primi- 

 tive method, each striking -phenomenon being elevated to 

 the dignity of a disease. Consequently a certain infection, 

 by causing a wide variety of outstanding phenomena, in- 

 jected into veterinary literature numerous alleged "dis- 

 eases" each due to a single infection. It was unavoidable 

 also that a given phenomenon, such as fetal death, which 

 may be due to numerous different infecting agents, should 

 be known as one disease. Thus abortion, metritis, retained 

 fetal membranes, epididymitis, semino-vesiculitis, and dys- 

 entery of the new-born, all of which in a given series of 

 cases may be due to an identical infection, have been de- 

 scribed as six distinct diseases and scattered from end to end 

 of veterinary literature. 



The re-casting of the genital diseases of animals into a 

 systematic treatise is a formidable task, the first effort at 

 which must be very imperfect. In 1909 I published "Vet- 

 erinary Obstetrics; Including the Diseases of Breed- 

 ing Animals and of the New Born", in which many of 

 the diseases of the genital organs were included under the 

 primitive plan. It was abandoned at the exhaustion of the 

 first edition. In 1917 I published "Veterinary Obstet- 

 rics" and began the preparation of the present volume. The 

 two treatises have been designated "companion volumes" 

 because they are closely allied in subject matter and may be 

 profitably studied together. 



The present treatise appears at a critical period in the 

 history of the diseases of the genital organs of animals, 

 when an old, firmly entrenched belief is slowly crumbling 

 and a modern one is struggling for recognition. Abortion 

 has long been regarded as a specific infectious disease, due 

 in a given species of animals to one bacterium and to one 

 only. If an exception arose and a given abortion or group 

 of abortions was apparently due to an infection other than 

 that specified for the species of animal concerned, it was not 

 infectious abortion but merely abortion due to infection. 



The belief in a specific infectious abortion has occupied 



