Conclusion 69 



I think I can omit here a further comparison of the 

 doctrine of pangenesis with the theories established by 

 other investigators. Substantially it is contained in my 

 criticism of those views, and besides it will follow from 

 the working out of the fundamental thought in the suc- 

 ceeding paragraphs. 



12. Conclusion 



The considerations of the first division of this Part, 

 and the critical explanations of the second division, have 

 led us to recognize, as unavoidable, a hypothesis of the 

 material basis of hereditary characters. It is, in a cer- 

 tain sense, a postulate at which everybody must more 

 or less surely arrive who thinks upon these questions, 

 and which we have always been able to trace as the kernel 

 of the best theories of inheritance. 



Let us conclude now by presenting this hypothesis in 

 the most simple manner possible, and by indicating the 

 most important explanations which it is able to give us 

 without ancillary hypotheses. 



In the first Division we arrived at the conclusion that 

 hereditary qualities are independent units, from the nu- 

 merous and various groupings of which specific charac- 

 ters originate. Each of these units can vary independ- 

 ently from the others ; each one can of itself become the 

 object of experimental treatment in our culture experi- 

 ments. 



Hereditary characters are connected with living mat- 

 ter, and heredity depends on the fact that children origi- 

 nate from a material part of their parents. The visible 

 characteristics of organisms are determined by the invisi- 

 ble characters of the living matter. In this living substance 

 we assume special material bearers for the individual 

 hereditary characters. This is the fundamental thought 



