1893.] 1J5 [Ryder. 



the early stages of segmenting eggs are known by the thousand to the 

 skilled enibryologist. 



In that these cannot at first be overmastered by either phylogenetic or 

 ontogenetic forces, or by both combined, proves that the forms so devel- 

 oped are, therefore, the resultants of the energy represented by the phylo- 

 genetic and ontogenetic or the sum of the liereditary forces working in 

 antagonism against a recurring statical condition of the substance of the 

 germ. This statical condition reasserts itself at the close of every seg- 

 mentation, so that there is a recurrent conflict between these two sets of 

 forces at every step of development. In fact, the round or oval form of 

 the egg is a statical condition of the geiminal mass dependent wholly or 

 partially upon its own surface-tensional properties. That this is gradually 

 overcome in the course of the ontogenetic process is well known, but it 

 is also a fact that no known form of animal or vegetable development is 

 exempt from the influence of the interference of statical forces of equi- 

 librium, mainly those of surface-tension. In so far, therefore, as the form 

 of the early stages of the development of an embryo are thus interfered 

 with, such modifications are statogenetic. The great generality of this 

 principle, therefore, becomes apparent. The generality of statogeny is, 

 in fact, coextensive with that of phylogeny and ontogeny. But this is 

 not all. Every statogenetic state alternates with a kinetogenetic state, 

 since every new statogenetic condition is heralded by a kinetogenetic one. 

 It is this incessant organic and organizing seesaw of processes that is 

 comprehended under the still more general term of ergogeny. 



Such must, therelore, be my excuse for adding this new set of terms to 

 those already in use, since they represent a series of processes of such 

 universality as to be of an importance second only to those of phylogeny 

 and ontogeny. To illustrate in detail the great variety of phenomena 

 with which ergogeny and its forms, kinetogeny and statogeny, have to 

 deal would much transcend the purposes of this paper. Only sufficient 

 additional examples will therefore be given to show the far-reaching char- 

 actei of these principles. 



In the motion of Amceba proteus, kinetogenetic phenomena either alter- 

 nate rhythmically with statogenetic phenomena, or perhaps more correctly, 

 both constantly accompany one another in the course of the movements 

 made by this very simple organism. The chemical processes within the 

 Amo3ba by means of which its surface-tension is constantly being disturbed 

 are kinetogenetic, since this equilibrium or statical Inilance of the plasma 

 is thus recurrently overthrown. This leads to a temporary rupture of the 

 surface layers of molecules and an intrusion of new molecules from within 

 to repair the rent. When this is accomplished a statical equilibrium is tem- 

 porarily restored only to be followed by a recurrence of motion or over- 

 throw of statical equilibrium. This leads to the more or less fitful or 

 interrupted motion seen in these organisms. These alternating and con- 

 flicting processes also determine the figure of the organism at every instant, 

 so that ergogeny becomes, in the lowest forms, through its elementary 



