u6 PHYSIOLOGICAL 



A study of the correlated changes which characterize the 

 oestrous or sexual cycle in female animals supplies evidence 

 of the truth of the same principle. It has been observed that 

 in the early stages of pregnancy when the foetus is still small 

 and the developing mammary tissue inconsiderable, there is 

 often a tendency to put on fat. This tendency is associated with 

 the cessation of the "heat" periods, a cessation which implies 

 the arrest of ovulation (i.e. the discharge of eggs from the 

 ovary) and those other characteristic phenomena of oestrus 

 which manifest themselves externally in the display of sexual 

 feeling, and involve a considerable expenditure of vital energy. 

 Subsequently, however, when the need for nourishing the 

 rapidly growing calf involves a serious drain upon the mother, 

 and when the developing mammary tissue is in a state of 

 great activity preparatory to parturition, the tendency to fatten 

 induced by the "settled" condition of early pregnancy ceases, 

 for the functional activities of the mother as pregnancy proceeds 

 tend more and more to become subservient to the needs of the 

 offspring. 



The changes which occur periodically in the ovary are clearly 

 intended (to speak ideologically) to secure this end, that is to 

 say, in the normal condition they are regulated with a view to 

 fecundity, and to co-ordinating the activities of the generative 

 organs and mammary glands so as to produce a minimal amount 

 of waste in the energy expended upon these processes. 



The two ovaries (which are placed symmetrically on the right 

 and left sides of the body cavity) are the essential reproductive 

 organs of the female, just as the testicles are the essential male 

 organs. The other female organs (the oviducts, the uterus, 

 womb or " bed," the vagina or common uro-genital passage, etc., 

 and the mammary glands) are to be regarded as accessory, and 

 the periodic changes which take place in them are dependent 

 upon the varying activities of the ovaries. The ovary is like the 

 mainspring of a watch, it governs all the sexual functions and 

 controls the oestrous rhythm, and if it be removed the cycle 

 ceases, and sooner or later atrophy sets in among the accessory 

 organs. Just as the rhythmic movements of the hands of a 

 watch or clock, both the short and long hands and the 



