90 THE BIOLOGICAL PROBLEM OF TO-DAY 



instance, the size, structure, veining, and shape of 

 leaves, the characteristic and often absolutely 



/ 



constant patches of colour on the petals of flowers, 

 such as orchids, may be referred to similar causes. 

 These qualities can only arise by the regular co- 

 operation of many cells.' 



Notwithstanding so correct a declaration, Weis- 

 mann himself, in his doctrine of determinants, has 

 fallen into the error he himself has exposed. To 

 represent characters of the adult due to groups of 

 cells and organisms, he imagines in the egg-cell, 

 not simple particles like pangenes, but architec- 

 turally arranged groups of particles, determinants. 



No real change has been made. Conditions are 

 reflected upon the cell that in their real nature 

 surpass its possibilities. With right and reason one 

 may adduce, against his own determinants, what 

 Weismann has said about pangenes, for exactly the 

 same reasons : ' There cannot be zebra-determinants 

 or serration-determinants, because zebra- striping, 

 like the serrated edge of a leaf, is no cell character.' 



The error in Weismann's doctrine of determinants 

 may be made clearer by an analogy. 



The human state may be conceived as a high 

 and compound organism that, by the union of 

 many individuals, and by their division into classes 

 with different functions, has developed into a form 

 always becoming more complicated. To carry out 

 our comparison better, let us assume that all the 

 individuals united in the human state arose from a 

 single pair. The single pair would be the rudiment 

 of the whole state, and would bear the same signifi- 



