TYPES OF (ESTROUS CYCLE 



59 



amount of milk in the ducts. During pregnancy the growth of 

 the mammary glands for the first fourteen days is similar to that 

 found during pseudo-pregnancy and is lateral and radial only. 



Fig. 32. — Photograph of Mammary Gland of Rabbit 



TWENTY-THREE DAYS PrEGNANT. 



Great hypertrophy of the gland, characterized by secondary 

 thickening, has begun. 



In the second half of pregnancy an entirely new phase of 

 mammary growth is initiated, i.e. a thickening of the gland, 

 during which the different nipple areas become confluent. The 

 tissue reaches a thickness of some •3--4 cms., and the glands 

 weigh about 100 gms. at the end of pregnancy. 



