Generation and Development. 381 



The ripened bladder-like Graafian vesicle comes to the 

 surface of the ovary and bursts ; but before this occurs, the 

 fimbriated expansion of the Fallopian tube has embraced 

 it, the ovum passes into the canal, and, by means of the 

 cilia which line it, is impelled towards the uterus. In the 

 Fallopian tube it meets with the male element, and impreg- 

 nation of the ovum occurs in a manner which will be 

 presently described. Should the fimbriae of the Fallopian 

 tube fail to grasp the vesicle, the ovum falls into the 

 abdominal cavity and there perishes, or, if it has already 

 met with the male element, an extra-uterine foetation 

 occurs. 



The period of heat manifests itself at different times : 

 the mare is ' in season ' during the spring and summer, the 

 period lasting two to four days, and recurring every three 

 or four weeks ; during the interval the male is not accepted. 

 The cow is much the same as the mare ; sheep take the 

 ram in the autumn. 



The male is attracted to the female by a peculiar smell, 

 which can even be detected by the former at some con- 

 siderable distance. 



The number of ova discharged at each period varies : 

 generally one for the mare and cow is the rule, though two 

 may be discharged ; one to four for the sheep ; whilst the 

 pig may discharge ten or more ova at one time. 



The Period of Puberty, or that time in the animal's life 

 when it is capable of procreation, has been put at 3 years 

 for horse and ox, and 12 months for the sheep ; the 

 females may conceive at an earlier period than this — in 

 fact, commonly do. A mare may conceive between 12 

 months and 2 years, a cow 12 to 18 months, sheep and 

 goat 8 to 12 months. The use of immature mares for 



o 



breeding stock is the explanation of a great deal of the 

 worthless material in the shape of horseflesh which may 

 be seen in this country. In my opinion, neither mare nor 

 horse is fully developed, mature, or fit for procreation until 

 5 years old. 



The advent of maturity is marked by certain changes in 



