288 The Living Plant 



a new plant is developed. Now the difference between the two 

 cells is known to consist in this, that the larger possesses a store of 

 food substance, which is used in giving a start to the new individ- 

 ual, the presence of this food substance in the cell being re- 

 sponsible both for its larger size and its loss 

 of locomotive power. The smaller cell, on 

 the other hand, contributes no food for start- 

 ing the offspring, but elaborates the features 

 concerned in locomotion, thus ensuring that 

 the two cells shall be brought together. This 

 difference does not imply in the least that 

 the two cells contribute differently to the 

 the left is a single one offspring, for the food substance supplied by 



and at the right a pair , M.I 



in process of fusion, the larger cell has no more to do with de- 

 Chi " termining the essential characters of the new 



individual than has the food we eat in 

 determining our essential characters; the characters are de- 

 termined by the chromatin in the nuclei, which the two cells 

 contribute equally. But in this comparatively minor feature of 

 division of labor between the two kinds of cells we have the origin 

 of sex, for the larger cell we recognize as female and call it the egg- 

 cell, and the smaller we recognize as male and call it the sper- 

 matozoid (or antherozoid). This difference between a large 

 immobile egg-cell and a tiny active male cell, once established, 

 persists and prevails in principle, though with numerous varia- 

 tions of detail, throughout all of the more highly organized plants, 

 and throughout all of the higher animals, inclusive of man; and it 

 is the foundation of all the phenomena of sex. 



The essential characters of the sexual cells being thus estab- 

 lished in these comparatively low plants in a degree of develop- 

 ment as high as they ever attain, the sexual developments in the 

 higher plants are concerned not with the sexual cells, but with the 

 various accessory structures contributing to ensure fertilization 

 under the conditions to which those plants are exposed. A first 



