44 INTRODUCTION TO SEXUAL PHYSIOLOGY 



In both pregnancy and pseudo-pregnancy the uterus under- 

 goes certain changes which relate chiefly to the blood vessels 

 and glands of the mucosa. These increase in size, the whole 

 organ assuming an appearance indicative of great activity. 

 The secretion coming from the glands is a source of nutriment 

 to the foetus during pregnancy, and is similar to what in ungulates 



sec. 



hi. 



Fig. 25. — Section through pro( L'strous uterine mucosa of dog. 

 (From Marshall and Jolly.) 



ex. bl., Extra vasated blood corjjuscles ; pol//m.., polymorph ; 

 sec.y cells probably indicating secretory activity. 



is called " uterine milk " ; in pseudo-pregnancy a fluid is like- 

 wise secreted as if intended for a foetus. The growth changes in 

 pseudo-pregnancy are less pronounced than in true pregnancy, and 

 are succeeded after four or five weeks by degenerative changes 

 when the glands become shrunken, and their epithelium, from 

 having been columnar, becomes cubical, and some of the cells 

 are desquamated into the lumen. At the same time there is 

 haemorrhage from the vessels but without leading to external 

 bleeding. 



Contemporaneously with the growth of the corpus luteum 

 and uterus, the mammary glands also develop during both 



