142 CYCLIC CHANGES IN THE OVARIES AND UTERUS OF THE SOW, ETC. 



of low epithelium with surface protuberances or roughening may quite as plausibly 

 be considered not a degenerative phase, but one of physiological significance, in 

 some way. (See page 143.) 



PREVIOUS ACCOUNTS OF THE UTERINE MUCOSA OF THE SOW. 



Certain previous contributions to the cyclic anatomy of the pig's uterus de- 

 serve consideration at this point. Givkovitch and Ferry (1912) attempt a direct 

 comparison between the changes of the human menstrual cycle and those of the pig's 

 uterus. They describe, without giving the time relations, four stages of the corpus 

 luteum: formation, full development, early and advanced involution; and they 

 correlate with these stages four steps in the condition of the uterine mucosa, which 

 they call prehyperamic, hypersemic, posthypersemic, and interval. Such a division 

 does not disagree with our present description, although we have not seen all the 

 histological changes mentioned by Givkovitch and Ferry. It is to be regretted 

 that their preliminary note has not been followed by a definitive account. 



Stegu (1912) interested himself chiefly in the question of distribution of the 

 uterine cilia. He had 60 animals at various stages of the cycle and made studies 

 of the fresh mucosa in all of these with fixed and sectioned preparations of 15 of 

 them. As a result of this work he has given the best account of the external fea- 

 tures of cestrus that the present writer has seen; he speaks of ovulation during 

 heat ; hints at the oestrous oedema of the uterine mucosa, and mentions the degenera- 

 tion of certain epithelial cells at this time. Being anxious to contrast oestrous with 

 definitely non-cestrous uteri, he had but one animal killed between the end of 

 cestrus and the tenth day thereafter; in this specimen he observed the hillocky 

 arrangement of the epithelium, with crypt-like depressions intervening, which we 

 have found to be characteristic of this stage. 



