272 LILLIE. [Vol. XVII. 



simple case of the segmentation of the intestine of the echinid 

 gastrula. 



" Here at first only two effects are produced ; the formation 

 of two constrictions takes place. That the effect happens to 

 be the formation of constrictions does not concern us here, for 

 it is founded on the potency of the system, and is only called 

 forth by the exciting cause ; but the cause is decisive for the 

 place of origin of the constrictions. As already said, we mtist 

 (italics mine) conceive of this cause as ' Fernkrafte,' more partic- 

 ularly as ' Fernkrafte ' acting at a particular distance. But the 

 distance of the effect {which is inherent) is not absolute, 

 because in gastrulae of any size, produced by operations, the 

 intestine segments equally well into the proper proportions ; 

 thus the effective distance of the ' Fernkrafte ' acting from one 

 end point of the system is given not as an absolute but as a 

 relative amount, being dependent on the length of the axis of 

 the differentiating system. 



" The establishment of heterogeneity affords new places for 

 new kinds of ' Fernkrafte,' " 2md so wetter. Driesch passes here 

 from saying in one paragraph we cafi represent the process by 

 assuming " Fernkrafte " acting from a fixed point, to the asser- 

 tion in the next that we must conceive of the cause as " Fern- 

 krafte." Hereafter, then, he regards his postulate as a logical 

 necessity, no longer a mere intellectual convenience, like ]\Iax- 

 well's demon, although it is an hypothesis of a precisely similar 

 nature. 



It is pertinent to ask whether in any extremity the assump- 

 tion of " Fernkrafte " is permissible ; but, passing this by, 

 the postulated force must either be a product of the system 

 or something independent of the system. If a product of the 

 system, when all parts are alike, it must be postulated of each 

 part ; each element then is not only bilaterally symmetrical, 

 but has a " Fernkraft " " seated " at one of its poles ; as soon 

 as the heterogeneity demanded by this is established, the 

 elements in each section become endowed with new kinds of 

 " Fernkrafte." Unless these arise absolutely de novo (!), they 

 must have existed in a latent form previously, and there would 

 appear to be no escape from the conclusion that each element of 



