296 E. G. S paiddnig 



is really incorporate in any special energy-law as species, just as 

 each special law is in turn incorporate in the concrete event. 



Any determination of the value of an energy-transfer can be 

 made only under the guidance of some knowledge or hypothesis 

 as to what factors are concerned and also only through the appli- 

 cation of some special energy-law such as the above, W = pv. But 

 by the above substitution and derivation, as a result of which we 

 could set 



it is shown that, when E, as the resultant energy decrease in an 

 isothermal process, has been computed through the substitution of 

 the values obtained by compensation methods for the initial and 

 final pressures, with the volume constant, this determination is 

 made in accordance with and through an empirical law which 

 is a special case of equation [8]. The energy-transfer so deter- 

 mined is accordingly brought under the principles which equation 

 [8] epitomizes. 



Any possible criticism, therefore, that the procedure here has 

 been in a circle, is no more valid than, or is as invalid as, it is in 

 any case of the genus-species relation. 



However, for the practical application of the fundamental equa- 

 tion to a change in a system under equilibrium conditions, it is 

 necessary, in order to be able to make the requisite experimental 

 measurements, not only to know what the general temperature 

 conditions, etc., are, but also there must be an insight as to what 

 other intensities and what extensity factors are directly concerned. 

 Then and only then can our experimentation, consisting in methods 

 of compensation, be adequately guided. 



Such an insight, now, is to be obtained, in some cases at least, 

 only by the forming of an hypothesis, a working point of view, 

 which, of course, shall be based on as well founded and as complete 

 data concerning the system in question as it is possible to get. 

 Such an hypothesis must, then, be now developed as to the nature 

 of those organic phenomena to which it is my purpose to apply the 

 general principles which we have elucidated. The segmenting fer- 

 tilized egg is the system whose changes are to be studied. 



