xni] 



FEMALE GENERATIVE ORGANS 



193 



in her second year, piiljerty generally occurring at about 16 to 18 

 months. Heifers take the bull at 12 to 14 months but may ex- 

 jDerience jjuberty earlier. The sow may take the boar at 4 or 5 

 months but j^ubertj' is generally later. Ewe lambs dropped in the 

 spring may breed in the following autmnn. Bitches and cats 

 experience puberty at 8 to 10 months, sometimes later, and 

 occasionally earlier. The time when reproduction ceases is very 

 variable and in practice most domestice animals die long before 

 they reach their menopause. Mares have bred ev^en at 30 years 

 and ewes at 21, but such cases are ver}^ excei^tional. 



Fig. 101. Louk sheep a^ed 18 years with her last lamb This sheep which 

 belonged to Mr William Peel of Knowleraere Manor, Clitheroe lived to be 

 21 after having 'io lambs, nine of which were triplets. (From Marsliall.) 

 From photograph supplied by Lieut. -Col. W. K. Peel. 



The Internal Ovarian Secretions. In addition to the oogenetic 

 function the ovaries are organs of internal secretion, and through 

 these exercise an influence over the female metaboUsm com- 

 parable to that possessed by the testes in the male. In birds 

 removal or atrophy of the ovaries tends towards the assumption 

 of certain of the male characters. Thus in female poultry there 

 is apt to be a development of the spurs, hackles and feathering of 

 the cock, and it is well known that old hens which have ceased 

 to lay often take to crowing. The relation between the ovaries and 



M. p. 13 



