THE NUCLEUS 7 



the wall, it cannot do its work without the influence of the 

 nucleus. (/>) We have good reasons for the belief that the 

 nucleus is the cause of oxidation in the living cell, and, without 

 it, the tearing down and building up processes of the cell that 

 depend upon oxidations cannot go on. (c) After the nucleus 

 has been removed the remainder of the protoplast soon dies. 

 While, on these grounds, the nucleus may be spoken of as the 

 center of life of the cell, the fact must not be left obscured 

 that a nucleus dissociated from the rest of the protoplast cannot 

 long maintain its existence, and the cooperation of the other 

 parts is necessary to the success of the functions of the nucleus. 



The nucleus is also frequently spoken of as the bearer of 

 the inheritable characters and qualities. This, too, is not with- 

 out foundation, and if true the nucleus stands forth as the 

 architect and master of the form, character, and activities of 

 the cell and entire plant body. The grounds for the assump- 

 tion are: (a) In the embryonic cells of the growing apex or 

 cambium the nucleus is relatively large, having an average 

 diameter 0.6 that of the entire cell. These cells are to undergo 

 profound changes in size, form, and general character as the 

 differentiation of tissues proceeds, and why should the nucleus 

 be allotted so much space within the cells unless it plays a domi- 

 nant part in the hereditary differentiations that are to follow? 

 The evidence here is enough to raise the question, but it does 

 not go far toward solving it. (fr) During nuclear and cell divi- 

 sion the nuclear reticulum, which is the essential part of the 

 nucleus, divides into many pieces with great precision, and these 

 pieces are equally distributed between the nuclei of the two 

 resulting cells. What but the vehicle of hereditary transmission 

 should require such exactness of distribution? Here again 

 the facts afford us hardly more than the suggestion of the ques- 

 tion, (c) In fertilization, when the sperm cell from the pollen 

 grain is fusing with the egg cell within the ovule, the sperm cell 

 consists almost entirely of nucleus, and the egg cell is relatively 

 rich in cytoplasm; yet the offspring may partake as much of the 

 peculiarities of the male as of the female parent. The inference 



