62 WALTER HEAPE. 



Thus the human female may exhibit a sexual season, a 

 pro-oestrum, and a period of oestrus, precisely like any other 

 mammal, and the homology of these processes in all mammals 

 is, in my opinion, established. 



A i-eview of the literature which treats of the relation be- 

 tween "heat" or "rut," as it is usually called, and men- 

 struation, resolves itself practically into an enumeration of 

 those who deny there is any ground for comparison, and those 

 who assert they are identical processes. I do not propose to 

 enter into a detailed criticism of the voluminous literature 

 which bears upon the subject, but will content myself witli 

 quoting the essence of the most frequent assertions whicli 

 are made for and against the homology of these processes, 

 and with briefly replying to them. 



Those Avho uphold the homology do so because — 



I. There is congestion of the generative organs during 

 both "heat" and menstruation. 



II. There may be a recurrence of "heat" as there is a re- 

 currence of menstruation. 



III. The discharge during "heat" may be of a menstrual 

 character. 



IV. From a phjlogenetic point of view the homology is to 

 be expected. 



These statements may be disposed of together ; so far as 

 they go they are true enough, but they are not in themselves, 

 separately nor collectively, conclusive evidence. 



Those who deny the homology do so because — 



1. The discharge during "heat" in the lower animals is 

 said to be mucus, while in the human female it is mostly 

 blood. 



2. The time of "heat" is said to be the only time the 

 lower animals will permit of coition, while sexual union 

 during menstruation is a very rare occurrence. 



3. "Heat" or "rut" is said to occur in both males and 

 females in the lower animals and to depend upon the seasons, 

 whereas in the human species it is said to be not so. 



4. After "heat" the female of the lower animals is said 



