MAMMARY GLAND AND LACTATION 



597 







Fig. 10.3. Sections of biopsy specimens from the mammary gland of a sow before and 

 din-ing parturition. A. Six days before parturition: the mammary alveoh are small and con- 

 tain a nongranular eosinophilic secretion. B. Two days before parturition: alveoli have in- 

 creased in size and fat globules are conspicuous. C. Fifteen hours before parturition: alveoli 

 are now distended with secretion which consists of an outer zone of eosinophilic material 

 and fat globules, and a central zone of basophilic granular secretion. D. During parturition: 

 alveoli contracted with folded epithelium and sparse secretion. (From B. A. Cross, R. F. W. 

 Goodwm and L A. Silver, J. Endocrinol., 17, 63-74, 1958.) 



