PREFACE 



No attempt has been made heretofore to describe system- 

 atically the genital diseases of domestic animals. The path- 

 ologic processes acting within the genital organs and inter- 

 fering with the ideal production of young are chiefly hidden 

 from view. Only certain phenomena caused by them be- 

 come apparent. Of these the most striking phenomenon is 

 the observed expulsion of a fetal cadaver, which is desig- 

 nated abortion. The observer is generally forewarned of 

 impending death of a born animal because it is commonly 

 preceded by visible injury or illness, but abortion produces 

 a profound impression because the death of a potentially 

 valuable unborn animal has occurred unseen and is re- 

 vealed only when the cadaver is seen to be expelled. This 

 tends to draw a veil of mystery about the event. If the 

 spermatozoon, unfertilized or fertilized ovum, or the small 

 embryo perishes, the dead cell or body is not observed and 

 therefore excites little or no comment. 



In the early history of medicine, certain striking phe- 

 nomena were regarded and described as diseases. When the 

 science of pathology became established, a rearrangement 

 of medical literature became necessary and the phenomena 

 became grouped about their causes, so far as known. It 

 followed that various phenomena which had been regarded 

 as distinct diseases were in some cases due to a common 

 cause. In other cases a phenomenon classed as a disease 

 has been split up because the phenomenon was inconstant 

 in its cause. In primitive veterinary literature glanders and 

 farcy were described as distinct affections, but later it be- 

 came known that the two supposed diseases were merely 

 separate phenomena resulting from one cause. Nasal gleet 

 occupied a prominent place in primitive veterinary litera- 

 ture, but as veterinary science advanced the phenomenon of 

 nasal discharge was split up, assigned in each case to the 

 disease of which it constituted one symptom, and nasal gleet 

 disappeared from the pages of veterinary literature. 



