60 Mr. W. Heape. The artificial Insemination of Mammals 



order to confirm them, Professor Pearson, Veterinary Professor at 

 the University of Pennsylvania, Philadelphia, was applied to, and 

 Mr. Francis Gralton very kindly forwarded to me a letter from Pro- 

 fessor Pearson, in which he states that the artificial insemination of 

 mares is practised on a number of stock-farms in America with fairly 

 satisfactory results ; and further, he adds, he himself has performed 

 the operation and attained success. 



The usual method adopted is, to allow the stallion to cover a mare 

 in the ordinary way, then, immediately after coition, to pass a hand 

 into the vagina carrying therein the nozzle of a specially constructed 

 syringe, to depress with the tips of the fingers the ventral wall of 

 the vagina at its anterior end, and draw up into the syringe the 

 seminal fluid which will collect in the depression so formed. The 

 same mare can then be inseminated by inserting the nozzle of 

 the syringe through the external os uteri and forcing some of the 

 semen into the uterine cavity, then the syringe can be withdrawn, 

 and other mares which are " in use " can be inseminated with the 

 remainder of the semen in a similar way. 



Another method is also in use in the United States, and in this case 

 gelatine capsules are used instead of a syringe ; these capsules are 

 filled with spermatozoa from the vagina of a mare which has been 

 covered ; they are then closed and gently forced through the external 

 os into the uterus and allowed to remain there ; the heat of the body 

 melts the gelatine, and the semen is set free. 



It is possible by either of these methods to inseminate several 

 mares with semen obtained from one single act of coition, and in this 

 way the usefulness of a valuable stallion may be vastly increased. 



The above operations on mares were conducted for the purpose of 

 overcoming certain causes which induced sterility, and for this 

 reason the semen was introduced directly into the uterine cavity. 

 What these causes actually were is not stated, but it is obvious that 

 certain defects which prevent mares from breeding in the ordinary 

 way can be overcome by artificially introducing the spermatozoa of 

 a horse into their uterus. 



The causes of sterility in mares are, apparently, very various. 

 Fleming (No. 6), in the couple of pages which he devotes to the 

 subject, briefly refers to many of them. Here we are only concerned 

 with the causes which prevent the passage of live spermatozoa from 

 the vagina into the uterus of an otherwise normally constituted 

 animal. 



An abnormal condition of the cervix uteri is more common than is 

 generally known, according to Fleming ; occlusion of the os, due to a 

 spasmodic contraction of the muscles of the cervix during coition ; 

 rigidity of the cervix ; hypertrophy of the tissue of the os ; and the 

 formation of false membranes, which serve to close the entrance to 



