The Multiplication of Pang ens 213 



protoplast every kind of pangen must be represented in 

 great numbers. In addition, the relative number of the 

 bearers of the individual hereditary characters is of very 

 great importance. In the cytoplasm it determines the 

 function of the individual organs, in the nucleus the power 

 of inheritance. If a new character in the nucleus is rep- 

 resented by only a few like pangens, the likelihood of this 

 character becoming visible, is evidently very small. But 

 the greater the number of those pangens, in comparison 

 with the others, the more prominent will the character 

 appear. From seeds of a twisted specimen of Dipsacus 

 sylvestris I have grown over 1 ,600 plants, of which only 

 two showed torsion of the stem. The pangens which 

 caused this torsion must, therefore, have been in such 

 relatively small numbers that their chance of becoming 

 active amounted to 1 per 1,000 at the most. In other 

 young varieties this proportion is more favorable, and, 

 by making the right selection, that chance increases quite 

 considerably in the course of a few generations. The 

 simplest explanation for this is obviously, that by breed- 

 ing those specimens in which the characteristic is repre- 

 sented by the greatest number of like pangens, the relative 

 number of these is gradually increased. 



I have repeatedly emphasized the fact that, according 

 to my hypothesis, the pangens can multiply in the nu- 

 cleus as well as in the cytoplasm. This multiplication is 

 of the same order as that of the cells and of the organ- 

 isms themselves. When a large tree bears, every year, 

 thousands of seeds, the pangens of the egg-cell from 

 which the tree has grown, must have multiplied in an in- 

 credible manner. And the same thing is taught by the 

 enormous number of eggs that a single tape-worm can 

 produce. In the face of such phenomena the multiplica- 



