224 DARWINISM TO-DAY. 



of the structure and functional capacity of invisible life-units, is 

 the sagacious one of Delage when he says that simply by the law 

 Delage's of probabilities it will be impossible by pure imagining 



criticisms. to explain correctly in detail the ultimate structure 



of protoplasm. Has any one, asks Delage, guessed in advance, with 

 the least truth, structures which the microscope has later been able 

 to reveal to us? Has any one guessed the cross-striation of muscles, 

 the cilia of vibratile epithelium, the prolongations of the nerve- 

 cells, the make-up of the retina, or the organ of Corti, the chromo- 

 somes, the centrosome? Distinctly not. Delage points out that 

 the chemists had a much better chance to hit the truth in supposing 

 atomic structure, for they had a much less complex condition to 

 perceive, and they had approached in their positive knowledge very 

 much nearer the hypothetical element which they adopted. 



Le Dantec criticises the micromeric theories of protoplasmic 

 structure by saying that all these theories seek to make mysteries 

 Le Dantec's clearer, complex things simpler, by reducing large 

 criticisms. things to small ones. A man, for example (he says) 



is composed of 60 trillions of cells and is nevertheless produced by 

 sexual elements of very small size; here is a phenomenon to ex- 

 plain. The micromerist says that the difficulty of this explanation 

 would be less (or at least not so sharply defined!) if one divided 

 the problem into 60 trillions of parts; that is, if one replaced the 

 reproduction of man by 60 trillions of partial reproduction. One 

 has therefore imagined particles infinitely small which are to the 

 cells what the sexual cells are to the man. And this comparison has 

 been, consciously or not. claims Le Dantec. the point of departure 

 of all the systems of particulate representation in the germ- 

 plasm. 



We have simply substituted for a single heredity, continues the 

 critic. 60 trillions of partial heredities, each exactly as mysterious 

 as the first. Thus these 60 trillions of gemmules gathered in the 

 egg and distributed in a precise manner are in reality only a dis- 

 guising of the homunculus of the ovalists. Perhaps we have no 

 reason to suppose that these gemmules design by their agglomeration 

 this invisible homunculus. but at least it is certain that they 

 are disposed in a manner which is in relation to the form of the 

 man to be determined, since in fact each of them represents not 

 alone a cell of the man, but a cell with the place it is to occupy. 



One sees thus how complex is this system which has for its aim 

 the simplifying of the question of heredity : it is more logical to 

 consider simply the egg as having the power to produce a man than 

 to attribute a power as mysterious to 60 trillions of gemmules to 

 which it is necessary to accord, in addition, a determinative capacity 



