104 AN11\IAL (iASTTIATION 



of six and nine months, and there is no good reason 

 why it should not be done at even an earlier age. In 

 collies or certain breeds of watch dogs, spaying is 

 best done at the age of six months, as there is a tend- 

 ency toward the accnnuilation of too much fat when 

 this operation is deferred nntil the subject has matured. 



Operating during the estral period should be avoided 

 if possible. While estrnm is manifested by a conges- 

 tion of the vulva, yet marked congestion of the ova- 

 ries and oviducts persists in some cases for weeks after 

 external signs of estrum have subsided. 



Anatomy of the Structures Directly Concerned. — 

 Since these aninuilx iire iiniltiparous, the uterine eorima 

 ai'e well developed and the body of the uterus is small 

 and rath(>r nnde\-eloped. The horns ai'e supported l)y 

 the Ijroad ligameuls which are of suffieient growth 

 usually to permit the ovaries being readily drawn to 

 the surface of an abdominal incision made at the linea 

 alba. The. ovaries are almost completely encapsulated 

 within the broad ligament; the size of the oviducts 

 varies materially in different sul)jects and not in pro- 

 portion to the size of the animal, — those having been 

 pregnant possessing o\'iducts proportionately larger 

 than those found in puppies not having reached the 

 age of puberty. During the estral period, the oviducts, 

 because of their congestion, are vei-y large, and this 

 fact serves to confuse the inexpei'icnced operator 

 whose tactile sense has not been trained to guide him. 



There are no other structural differences of the gen- 

 italia suffieien11>' important lo \\arran1 further con- 

 sideration. 



Preparation of the Subject. — Where the operation is 

 performed in a hospital efpiinped with proper facili- 

 ties for the safe handling of animals, the subject should 



