BEARERS OF THE HEREDITARY QUALITIES 63 



" The female nuclear material transmits the characters of the mother, 

 the male nucleus those of the father, to the offspring." Prof. Stras- 

 burger says for higher plants : " The process of fertilisation depends 

 upon the union of the sperm-nucleus with the nucleus of the egg-cell ; 

 the cell-substance (cytoplasm) does not share in the process ; the 

 cell-substance of the pollen-grain is only the vehicle to conduct the 

 generative nucleus to its destination." Prof. Weismann says: "We 

 can hardly ascribe to the body of the ovum a higher import than that 

 of being the common nutritive basis for the two conjugating nuclei." 

 Criticism. i. " The life of a complex multicellular organism cer- 

 tainly depends upon the inter-relations and inter-actions of many 

 parts ; the life of a cell apparently depends upon the inter-relations 



FIG. 16. A pollen grain, a, the two nuclei, with their chromosomes; 

 b, the general protoplasm ; c, the outer wall. (From Carnoy.) 



and inter-actions of different parts of the cellular organisation, 

 especially on the give-and-take between nucleoplasm and cytoplasm ; 

 and it is not unlikely that life itself i.e. vital activity or function 

 may depend upon the inter-relations and inter-actions of a number 

 of complex substances, none of which could by itself be called alive. 

 Just as the secret of a firm's success may depend upon a particularly 

 fortunate association of partners, so it may be with vitality." * 

 " We are compelled by the most stringent evidence to admit that 

 the ultimate basis of living matter is not a single chemical substance, 

 but a mixture of many substances that are self-propagating without 

 loss of their specific character." f Holding firmly to this view, 



* J. Arthur Thomson, Science of Life, p. 115 (London, 1899). 



+ E. B. Wilson, The Cell in Development and Inheritance (ist ed., 1896). 



