378 ON THE NUMBER OF POLAR BODIES AND 



would be absent ; and during the maturation of such germ -cells 

 no polar body would be formed for its removal. This view accords 

 with the fact that polar bodies are absent in many plants. Further- 

 more, I am far from maintaining that in the cases where polar 

 bodies occur, they must have the above-mentioned significance. 

 I only wish to point out that t t he reduction assumed to be neces- 

 sary for the nucleus of the vegetable germ-cells is not necessarily 

 to be sought for at the close of their maturation, but perhaps even 

 more frequently in an equal division of the germ-cells during some 

 period of their development. 



It also seems to me to be not impossible that a number of these 

 vegetative ' polar bodies ' may have an entirely different signifi- 

 cance, viz. to perform some special function accessory to fertiliza- 

 tion, as in the so-called ' ventral canal-cells ' of the higher crypto- 

 gams and conifers. As we know that even the two polar bodies 

 of the animal egg are not identical although externally they are 

 extremely similar, and although they arise in a precisely similar 

 manner I am even more inclined than before to consider that 

 the very various ' polar bodies ' of plants possess very different 

 meanings. 



But I do not feel justified in criticizing in detail the results of 

 botanical investigation. I must leave the decision of such ques- 

 tions to botanists, and I only desire to state distinctly that a ' re- 

 ducing division ' of the nuclei of germ-cells must occur in plants 

 as well as in animals. 



V. CONCLUSIONS WITH REGARD TO HEREDITY. 



The ideas developed in the preceding paragraphs lead to remark- 

 able conclusions with regard to the theory of heredity, conclusions 

 which do not harmonize with the ideas on this subject which have 

 been hitherto received. For if every egg expels half the number of 

 its ancestral germ-plasms during maturation, the germ-cells of the 

 same mother cannot contain the same hereditary tendencies, unless 

 of course we make the supposition that corresponding ancestral 

 germ-plasms are retained by all eggs a supposition which can- 

 not be sustained. For w r hen we consider how numerous are the 

 ancestral germ-plasms which must be contained in each nucleus, 

 and further how improbable it is that they are arranged in 



