102 THE PHYSIOLOGY OF REPRODUCTION 



goblet-shaped cells are frequently observable in the glandular 

 epithelium, and it is suggested that these are in some way con- 

 nected with the secretory activity of the glands. 



It is probable that destruction of the superficial epithelium 

 occurs normally to a greater or less extent both in the bitch and 

 in the ferret. Epithelial cells have been observed lying free in 

 the uterine cavity, while, in some sections, places have been 

 noticed where the stroma presented a raw edge, having been 

 stripped of its epithelial covering. In the bitch a layer of 

 flattened stroma cells may sometimes be seen in close attach- 

 ment to the epithelium during the process of denudation. In 

 the ferret it would appear that the destruction may occasionally 

 be severer, but it is thought that this is exceptional. It has 

 been pointed out, however, that a comparison between the 

 thickness of the uterine wall (and conversely the size of the 

 uterine cavity) in ferrets killed at the commencement of the 

 recuperation period and during the period of rest, is very sug- 

 gestive of a definite removal of stroma as well as of epithelium 

 in the process of destruction. 



Polymorph leucocytes have been observed in abundance 

 at this stage in the bitch's uterus, both in the stroma and also 

 in the cavity, and large mononuclear leucocytes (hyaline cor- 

 puscles), containing pigment derived doubtless from the ex- 

 travasated blood, have also been seen to occur. Large cells, 

 with faintly staining nuclei of very considerable size and con- 

 spicuous nucleoli, have been noticed at rare intervals lying in 

 spaces in the stroma tissue of the procestrous bitch. The origin 

 and significance of these cells are not known. 



There is no blood-clot formed in the uterus, either in the 

 bitch or in the ferret. 



(4) Period of Recuperation. The new epithelium in the bitch 

 is first seen as a layer of flattened cells which bear a resemblance 

 to the cells of the stroma. Its manner of formation is an open 

 question, but it would seem probable that it is derived mainly, 

 if not entirely, from the remaining cells of the old epithelium, or 

 from those of the glands. It is just possible, however, that 

 in certain places the epithelium may be renewed from the 

 underlying stroma tissue, as is said by Heape (but no.t by van 

 Herwerden) to be the case in the monkey. 



