110 The American Naturalist. [February, 



and we come to realize its great worth, reaching to the very 



boundaries of sex in its application and being a chief ele- 

 ment in the development of sex. < )f the very numerous illus- 

 trations given bv Geddes and Thompson, we can only select a 

 very few. 



The female cochineal insect, laden with reserve products 

 spends most of her time on the cactus plant as a mere quiescent 

 gall, while the male, on the contrary, is provided with wings, 

 agile, restless and short lived. Almost innumerable instances 

 of a similar character might he cited. Up to the level of 

 the amphibians the females are generally larger. A sluggish 



expenditure of energy uses up the reverse material and keep- 

 down the size. The large and small spores (macrospores and mi- 

 crospores) which we rind in plants, and which mark the begin- 

 ning of sex. illustrate the same law. Of sex cells in general, all are 

 familiar with the fact that the antherozoids and spermatozoids 

 are always much -mailer and infinitely more active than the 

 female cells. The agility of males it appears then is not a 

 special adaptation as Darwin suggested to enable them to better 

 and more surely perform their functions with relation to the 

 other sex, but is a natural characteristic of the constitutional 

 activity of males. 



. Body temperature which is an index to the pitch of life 

 is distinctly lower in females as observed in the human species, 

 insects and plants. 



A familiar and striking illustration of this law is found in 

 the process of menstruation, if it has been rightly interpreted. 

 You are likely, as physicians, more familiar with the various 

 theories of menstruation than I. Probably the most generally 

 accepted one is " that which regards the growth of the mucus 

 coat before fecundation as a preparation for the reception of 

 an ovum if duly fertilized, and the menstruation process itself 

 as the expression of the failure of these preparations.' 7 If we 

 express it now in terms of the anabolic-katabolic law, or the 

 anabolic highly vegetative character of the female, menstrua- 

 tion is the means of getting rid of the anabolic surplus in case 



