1890.] xdi [Ryder. 



affect the peristaltic contraction of the oviducts, the enclosure of the 

 ovary hy the fimbria? leading to conditions favorable to the emission of the 

 egg at the time of coitus. 



In animals, the provisions for rendering the male elements more effi- 

 cient are thus rendered more perfect. There is not wanting evidence that 

 the glans penis mav serve as a sort of piston, fitting closely against the 

 sides of the vaginal passages so as to prevent the regurgitation and loss 

 of the semen. In mice I have observed that in those which have recently 

 been in coitus, the uterus is actually distended with semen. These con- 

 trivances, many of which are of the most singular conformation, as that 

 of the pig, for example, probably serve the purpose of more efficiently 

 carrying the seminal matter into the genital passages of the female where 

 the}' are to subserve the essential purposes of reproduction. At any rate, 

 the wonderful contrivances in the higher plants serving the purpose of 

 efficient fertilization are no more remarkable than those in the higher 

 animals, the study of which has been singularly neglected by physiolo- 

 gists. 



In the lowest types of living forms there is nothing which suggests in 

 any way the gratification of passion. The mere tendency towards conju- 

 gation of animals and plants without nerves cannot be identified with an 

 appetency arising from ati3'' pleasure experienced in such conjugation. 

 There are at first no provisions made for conjugation except such as the 

 accident of contiguity of the conjugating elements as the germinating 

 spores of Myxomycetes, the intracellular spores of Hydrodictyon, etc. 

 When the process is so primitive as this, there is no evidence to show that 

 it is anything more than the expression of the cessation of one order of 

 tilings at the termination of one set of external conditions giving place to 

 a new order of things under the stimulus of a new set of outward condi- 

 tions more favorable to growth. Under this view of the case the incipi- 

 eucy of conjugative phenomena is simply the 1 expression of a readjust- 

 ment of the processes of growth under the influence of more or less 

 favorable conditions of life. The physiological traits of that life are ex- 

 pressed in the mode of molecular aggregation and constitution of the cel- 

 lular unit or units composing the individual. Its tendencies are to 

 increase the mass of the individual by processes of integration of new 

 matter in the course of which such new matter becomes molecularly iden- 

 tical with that of the organism engaged in such integration, a process 

 commonly expressed by the term assimilation. 



The consequence of such newer integrations are that still other inte- 

 grations are possible, under favorable conditions, on a much larger scale 

 than the first ones. The increased power to make continuously more and 

 more extensive and rapid integrations of identical molecules is possibly in 

 some way due to the increase of mass and surface and the consequently 

 increased capacity to liberate energy, or to perform work in a still more 

 active integration and assimilation of molecules. 



The Malthusian principle therefore rests, in its last analysis, upon a 



FROC. AMER. PHILOS. SOC. XXVIII. 132. R. PRINTED JIAY 27, 1890. 



