4 Author's Introduction 



throws off minute granules 1 which accumulate in the germ 

 cells and buds. These granules are the bearers of the 

 characters of the cells from which they are derived, and 

 thus transmit those characters to the germ cells and to the 

 buds. 



Thus all the hereditary characters of the organism 

 are represented in the egg-cells, pollen-grains, sperm- 

 cells, and buds by minute particles. These they have re- 

 ceived, partly by descent from former germ cells, i. e., 

 directly, but partly by later addition from the cells and 

 organs of the body. These minute granules are not the 

 chemical molecules; they are much larger than these and 

 are more correctly to be compared with the smallest 

 known organisms. Darwin calls them gemmules (small 

 germs). * 



The hypothesis of these gemmules threw an unex- 

 pected light on a series of facts which had hitherto been 

 in absolute darkness. And if one reads attentively Dar- 

 win's discussion, he sees more and more clearly that the 

 transmission of gemmules by cell-division, from the 

 mother-cell to the daughter-cell, suffices to explain large 

 groups of phenomena. Only isolated groups of facts de- 

 mand in addition the hypothesis of transportation. The 

 doctrine of latent qualities and of atavism particularly 

 are drawn from their former darkness by Darwin's hy- 

 pothesis, and his discussion of this subject (p. 357) 

 clearly shows what great significance he imputes to this 

 circumstance. It demands, however, only the transmis- 

 sion of the gemmules in cell-division, not their transpor- 

 tation from the growing and full-grown organs to the 

 germ-cells. 



1 This is the term Darwin first uses. The Variation of Animals 

 and Plants. 2: 358. New York, 1900. Tr. 



