92 THE BIOLOGICAL PROBLEM OF TO-DA Y 



But what applies to the causal relations between 

 the state-organism and men applies also, ceteris 

 paribus, to the explanation of the causal relations 

 between the rudiments in the egg and the organism 

 to which the egg gives rise. For these an explana- 

 tion cannot be expected on the lines of Weismann's 

 doctrine of determinants, as that implies a funda- 

 mentally erroneous assumption. It refers organi- 

 zations that depend upon cell-communities to 

 organizations of material particles within a cell. 



'To understand inheritance,' says Naegeli, with 

 truth, c we require not an independent, special 

 symbol for every difference resulting from time, 

 space, and quality, but a substance that, by the 

 linking of the limited number of elements in it, 

 can exhibit every possible combination of differ- 

 ences, and that by permutation can pass into 

 another combination of differences.' 



This standpoint is clearer when interpreted in 

 terms of cells. The hereditary masses contained 

 in the egg and spermatozoon can be composed only 

 of such particles as are the bearers of cell-characters. 

 Every compound organism can inherit characters 

 only in the form of cell-characters. The innu- 

 merable, and endlessly variable, characters of plants 

 and animals are of composite nature. They find 

 their expression in differences of shape, structure, 

 and function in the organs and tissues, and in the 

 special methods in which these are interrelated. 

 They depend upon the co-operation of many cells, 

 and, for this reason, cannot be carried into the 

 hereditary mass of any cell by material bearers. 



