so WALTER HEAPE. 



varies, to such an extent, indeed, that, while some women lose 

 a large amount of blood at each pro-cestrum, others sometimes 

 and some never lose any at all. It is not surprising, there- 

 fore, to find that while some observers hold that no change 

 takes place in the uterine tissue during pro-oestrum, others 

 state that highly specialised decidual tissue is formed at that 

 time; while some deny that even a portion of the uterine epi- 

 thelium is lost by denudation during pro-oestrum, others 

 maintain that the whole of the mucosa layer is discarded 

 during that process. 



The question has been somewhat fully discussed by me in 

 a former paper (Heape, 1894), where an account is also given 

 of the more important literature of the subject. Here it is 

 only necessary to add the conclusions arrived at, which are 

 that in all essential points the menstruation or pro-oestrum of 

 the human female is identical with that of monkeys. More 

 recently I have described (Heape, 1898) two menstruating 

 human uteri, the first of which shows congestion and is closely 

 comparable to Stage IV of the monkey, while the second 

 shows denudation, and appears to be practically identical 

 with Stage VII of the monkey. 



A slightly earlier condition of denudation in the human 

 uterus has been described and figured by Minot (1892), and 

 again supports the view above expressed. 



Among lemurs, Stratz (1898) has described what he calls 

 bloody " menstruation " for Tarsius spectrum. I gather 

 that, in this animal, denudation of the epithelium of the uterus 

 takes place and that Stage VII exists ; but there is no pi'oof 

 that denudation extends to the stroma tissue, and therein possi- 

 bly lies the difference between lemurs and monkeys, otherwise 

 there can be little doubt of the homology of the process in 

 these two animals. 



Stratz has also described the existence of a blood-clot and a 

 " menstrual" ^ flow in Tupaja javanica, and here again the 



' The use of tlic term " menstrual " flow, as it is here used, to denote a 

 flow of blood from the uterus, without regard to the periodicity of that 

 flow, is to be deprecated. 



