The Energy of Segmentation 313 



by the hypothesis formed that in cleavage we are deaHng with 

 "forces" which are efficacious only as resultant pressures, and, 

 second, by the nature of the factors actually determined by meas- 

 urement, again pressures, that it is the "volume energy" which is 

 so concerned. This "volume energy," here the energy of the col- 

 loidal solution, is a function, first, of the number of molecules or 

 of particles, and of their velocity, and, therefore, second, of the 

 chemical splittings and combinings, and of the temperature, 

 respectively. 



With the temperature and volume constant, tlie decrease in vol- 

 ume energy demands a correlative decrease in the number of mole- 

 cules, or of colloidal particles, or of both, as accompanying cleav- 

 age. This decrease would take place as a result in turn of a com- 

 bining, to a definite degree of course, of molecules and of particles, 

 which chemical change would be accompanied by the passing of 

 energy from the system (ovum) to the environment in the form of 

 heat. At least part of the "resultant" decrease in the volume 

 energy of the system is to be accounted for in this way. Con- 

 cerning the remainder of the decrease the evidence shows that its 

 reappearance is in the form of the increase in the energy of 

 the surface and in the mechanical energy or work done in the 

 moving of the "mass" surrounding the system as environment. 

 Under normal conditions it is with the intensity of the "surface 

 pressure" equal to the opposed intensity from within that an 

 equilibrium of form continues. 



What now, finally, is the meaning of the fact that it has been 

 possible to determine the energy of segmentation according to the 

 method presented ? That meaning I propose to summarize, for I 

 beheve it stands firm, even on the basis alone of the limited numer- 

 ical results obtained. 



As a first step in the demonstration it was necessary to state 

 briefly the principles which it was my purpose to apply, etc. These 

 were then formulated and shown to be epitomized in the funda- 

 mental equation 



dW 



The "work integral" was then shown to be a special case of this 



