PRESENT ASPECTS OF EVOLUTION 293 



First, so to speak, the corps separate to preside over 

 the formation of different body regions. Then the 

 different divisions, brigades, and regiments, composing 

 each next higher unit, separate, being detailed to form 

 ever smaller portions of the body. The process of 

 changing germ-plasm into somatoplasm is one of disin- 

 tegration. The germ -plasm contains representatives 

 of the whole army ; a somatic cell only representatives 

 of one special arm of a special training. Germ-plasm 

 in the egg is like Humpty-Dumpty on the wall ; soma- 

 toplasm, like Humpty-Dumpty after his great fall. 



I use these rude illustrations to make clear one 

 point : Germ -plasm can easily change into somatoplasm, 

 but somatoplasm once formed can never be reconverted 

 into germ-plasm, auy more than the fallen hero of the 

 nursery rhyme could ever be restored. 



The germ-plasm is, according to Weisinann, a very 

 peculiar, complex, stable substance, continuous from 

 generation to generation since the first appearance of 

 life on the globe. It is in the body of the parent, but 

 scarcely of it. Its relation to the body is like that of a 

 plant to the soil or of a parasite to its host. It re- 

 ceives from the body practically only transport and 

 nourishment. It is like a self - perpetuating, close 

 corporation ; and the somatoplasm has no means of 

 either controlling it or of gaining representation in it. 



Says Weisrnann* : "The germ-cells are contained in 

 the organism, and the external influences which affect 

 them are intimately connected with the state of the or- 

 ganism in which they lie hid. If it be well nourished, 

 the germ-cells will have abundant nutriment ; and, 

 conversely, if it be weak and sickly, the germ-cells will 



* Essays upon Heredity, p. 105. 



