30 THE STOCK OWXEK S ADVISER. 



at or near the end of eleven calendar months in the mare, and at 

 the end of nine and a half in the cow, is not easy to explain. 

 That the uterus loses its anatomical connection with the fully 

 developed and independent fetus is simply a fulfillment of the 

 laws of reproduction. So true, so admirable, and energetic are 

 the manifestations of the vital instincts of the uterus on this 

 occasion that they seem almost like intelligence. Dunglison 

 says: "With respect to the causes that give rise to the extru- 

 sion w^e are in utter darkness. It is in truth as inexplicable as 

 any of the other instinctive operations of the living machine. 

 Our knowdedge appears to be limited to the fact that when the 

 fetus has undergone a certain degree of development, and the 

 uterus a corresponding distention and organic changes, its con- 

 tractility is called into action, and the uterine contents are beau- 

 tifully and systematically expelled." 



CAN SEX BE PRODUCED AT WILL? 



To be able to determine the sex of embryo in animals would 

 greatly advance the art of breeding. From the observation of 

 During on this subject, I think we may safely conclude that 

 among animals and plants, as well as in mankind, a favorable 

 environment causes an excess of female births and an unfavora- 

 ble environment an excess of male births. As the result of 

 nearly a million observations of the births of colts, he shows 

 that, as the number of mares put to a stallion in a year is in- 

 creased, there is a corresponding and regular increase in the 

 niunber of male colts as comjiarcd with the female colts. He 

 states that, while domesticated animals are much more proliiic 

 than their wild allies, there is also a much greater preponderance 

 of female births; that wiien animals are taken from a warm to a 

 cold climate the ratio of male births increases, and that leather 

 dealers say that they obtain most female skins from fertile coun- 

 tries where pastures are rich, and most male skins from more 

 barren regions; and he thinks we may safely conclude that the 

 lower animals, as well as man, give birth to the greatest number 



