294 DRIESCH'S THEORIES OF DEVELOPMENT V 



for it is concerned in the acquisition of the food. It is invariably 

 present ; the others may or may not, some or all, be present. 



Some animals are also possessed of a capacity of locomotion, 

 and the performance of this function requires again a special 

 kind of soul. 



Lastly, there is the reasoning soul (SicuwjriKTJ), or mind (vovs). 

 This is found in man alone, unless there be other beings similar 

 to him, or even nobler than he. Mind alone is eternal and 

 separable from the body. 



In all reproduction (except in generalio equivoca) the starting- 

 point of a new individual is what Aristotle calls a o-Wp/xa. In 

 plants, in which he does not recognize the sexes, this is the 

 seed ; in sexually produced animals it is the result (KVJJ/XO) of 

 the mingling of the male (yovri, or oWpM in a narrower sense) 

 and female elements ; the latter is an egg or, in Mammals, the 

 catamenia. 1 



This o-nepua, he holds, does not come from all the organs of 

 ' the body by a kind of pangenesis, but is a tissue, homogeneous 

 like bone and flesh, and separated out from the food in its final 

 stage of digestion, when it is in the form of blood and ready for 

 assimilation, and hereditary resemblance is explained by the fact 

 that the food which is about to be assimilated by the organs is 

 naturally like that set aside to form the o-Trep/za. 2 



In the matter of the o-Tre'p/xa all the parts of the organism that 

 is to be formed are indeed present potentially, but this means 

 no more than that the material is there. 3 Actually (erepyeia), 

 they cannot be present until the soul has been developed, and in 

 particular the soul that is characteristic of animals, the perceptive. 4 

 Out of this matter the organs are differentiated successively, the 

 heart first, not only as a matter of observation (on the chick), 

 but as a theoretical necessity, since in it is the principle of growth, 

 then the blood, the blood-vessels, the tissues gathering about 

 these by a process of condensation and coagulation, the fore- 

 parts of the body first, and then the hinder. 5 The a-Wppta, then, 

 or Ki/jj/xa, is a material cause of development, but it is also 

 a cause in other senses ; it is the efficient cause, since it must 



1 De Gen. I. 18-20. 2 Ibid. I. 18, 19 ; IV. 1. 39. 3 Ibid. II. 4. 



4 Ibid. I. 19 ; II. 3, 5. 5 Ibid. II. 6. 



