Ryder.] J--L'± [May 16, 



the germinal elements before the latter are set free from the parent. The 

 attempt to formulate the laws of sexuality without examining into the 

 preembryonic history of the germinal elements must necessarily end in 

 failure and disappointment. The generative forces at work within the 

 parent organisms are nicely adjusted, or in a state of equilibrium with 

 those which are concerned, in the conduct of the ordinary physiological 

 activities of the parent body. It is, therefore, imperatively necessary to 

 consider the question of sex not simply as one involving embryological 

 data, but rather as embracing the sum total of physiological energies of 

 the parent organisms, and where the sexes are separate these energies 

 must be considered as represented in the species by the sexually differ- 

 entiated individuals composing the latter. 



It will be obvious to those who have kept pace with the growth of phy- 

 sical science, that sexuality may be thus brought more nearly within the 

 dominion of purely physical laws. In other words, sexuality is a ques- 

 tion involving the discussion of matter and its energy of motion, and 

 shovdd be so treated if it is expected to reach conclusions which are in 

 harmony with the genius of modern science. 



That such a project may be accomplished in the present state of our 



knowledge may well be doubted, yet there is ample reason to warrant 



- making an attempt to clear the ground for further work in that direction. 



The attempt to trace the ways in which one form of reproduction gave 

 place to a more complex one in the next higher type is beyond the scope of 

 the present paper. To consider this question adequately would require a 

 far more extensive acquaintance with the facts than is possible at present. 

 In plants it would require a consideration of the modifying effect of the 

 evolution of a mechanical supporting system and the correlative modifica- 

 tions which this must have induced in the sexual processes, since the 

 evolution of powerful supporting axes, which were capable of indefinite 

 growth, dichotomy, and consequent multiplication of fertile apical axes 

 enabled the plant to multiply the possibilities of the production of male 

 and female prothalli, or of protected and attached macrospores and dehis- 

 cent microspores. Not only this, but aerial currents would now become 

 available, as the plants become taller, in carrying the microspores, or 

 male prothalli, as pollen grains, from one flower to another. Finally, 

 this was supplemented by flying insects, which, it is fair to assume, first 

 began to visit the plants for the sake of their microspores or pollen as 

 food. Later, as these insects began to set up irritations in the flowers, 

 there is reason to think that the surfaces which they habitually abraded 

 would, if wetted with saccharine solutions regurgitated by such visitants, 

 begin to pour out additional nectar or saccharine matters in obedience to 

 well-known rules of ormotic action. That such a result would happen is, 

 at any rate, strongly indicated by the experimental results obtained by 

 my colleague, Prof. W. P. Wilson, in wetting abraded surfaces of leaves 

 with saccharine solutions. The elaboration of sweets so begun would 

 be a stimulus, causing the insect world to become still more interested 



