34 THE BIOLOGICAL PROBLEM OF TO-DAY 



upon this there follows a division of the general 

 body of the cell, i.e., of the protoplasm and its 

 contents. 



From the point of view of cells, I believe myself 

 compelled to raise several objections to most im- 

 portant bases of Weismann's germplasm theory. 

 For convenience of exposition these maybe divided 

 into two groups : Objections to the hypothesis of 

 differentiating division; objections to Weismann's 

 doctrine of determinants. 



I. OBJECTIONS TO THE HYPOTHESIS OF DIFFER- 

 ENTIATING DIVISION. 



A corner-stone of Weismann's theory is his 

 assumption of nuclear divisions which are differ- 

 entiating. Proof of this fundamental assumption 

 may be sought in vain in Weismann's writings. 

 Instead of that, a series of abstract arguments are 

 brought forward in favour of it. Thus on p. 31 

 (of the English translation) Weismann treats the 

 chromatin in the nucleus of the fertilised egg as 

 the substance which accomplishes inheritance, 

 and he denotes all the nuclei of the organism 

 arising from the nucleus of the egg by divisions as 

 the chromatin - tree, and then goes on to ask 

 whether or no the pieces of hereditary material 

 that make up the chromatin-tree of an organism 

 are like each other or different. ' It can easily be 

 shown/ the answer runs, ' that the latter must be 

 the case.' For ' the chromatin is in a condition to 

 impress the specific character on the cell in the 



