THE CELL DOCTRINE. 19 



his own. The doctrine of Wolf, as given by Prof. 

 Huxley, is as follows: "Every organ is composed, at 

 first, of a mass of clear viscous, nutritive fluid, which 

 possesses no organization of any kind, but is at most 

 composed of globules. In this semi-fluid mass, cavi- 

 ties (Blaschen, Zellen) are now developed; these, if 

 they remain rounded or polygonal, become the sub- 

 sequent cells, if they elongate, the vessels; and the 

 processs is identically the same, whether it is exam- 

 ined in the vegetating point of a plant, or in the 

 young budding organs of an animal. Both cells and 

 plants may subsequently be thickened by deposits 

 from the ' solidescible' nutritive fluid. In the plant, 

 the cells at first communicate, but subsequently be- 

 come separated from one another; in the animal, 

 they always remain in communication. In each case 

 they are mere cavities and not independent entities; organi- 

 zation is not affected by them, but they are the visible results 

 of the action of the organizing power inherent in the living 

 mass, or what Wolf calls the vis essentialis. For him, 

 however, this vis essentialis is no Archaeus, but -simply 

 a convenient name for two facts which he takes a 

 great deal of trouble to demonstrate : the first, the 

 existence in living tissues (before any passages are 

 developed in them), of currents of the nutritious 

 fluid determined to particular parts, by some power 

 which is independent of all external influence ; and 

 the second, the peculiar changes of form and com- 

 position, which take place in the same manner."* 



* Huxley, loc. citat., p. 293-4. Wolf, C. F., Theoria Genera- 

 tionis, 1759. Ed. Nova, 1774. 



