443 



volutionary speculation. I am prepared to admit with Strasburer 

 that the spore-mother-cell in archegoniates is the true beginning of 

 the sexual generation, but it must be clear that wide knowledge of 

 chromosome reduction in the Desmideae and in the Phaeophyceae, not 

 to mention other groups, is indispensible before the true nature of 

 alternation can be founded on these doctrines. 



It is demonstrable perhaps that the raison d'etre of antithetic 

 alternation as a characteristic of plants and not of animals lies in 

 the general automobility of sexual animals and the as 

 general non-automobility of sexual plants. Conjugation 

 in either phylum gives an opportunity for amphimixis to do its per- 

 fect work. Automobility in the animal phylum permits adjustment 

 with a varying environment to go on, which adjustment (Weismannism 

 aside) may be laid hold of by heredity. Jn the plant phylum most 

 fundamentally by rejuvenescence or by division (with isolation of the 

 blastomeres) or by both the same end is reached. By indirect 

 division of the syngamete — that is to say by the production of the 

 sporophyte , by the dissemination of the isolated blastomeres — the 

 environmental adjustment of each alternating species is enlarged and 

 this process atones for the lack of sexual automobility. 



Therefore under this view the profound diflerence between metazoan 

 devoid of alternation of the antithetic type and metaphytes charac- 

 terized by such alternation may be traced back to the fundamental 

 difference between plants and animals. For animals are relatively 

 dynamic , energy-liberating automobile organisms characterized by a 

 preponderance of katabolic changes while plants are as distinctly 

 static, energy-fixing, non - automobile and preponderantly anabolic in 

 their chemism. 



Hence sporophytization is as essentially a plant 

 character as cephalization is an animal. The one is an 

 expression, in the organism, of the static life, the other of the 

 dynamic. 



From these considerations it would appear that a very different 

 and possibly clearer interpretation of the relations between metaphytic 

 and metazoan reproductive processes than that of Beard may be given. 

 The essential point — the homologizing of coenogenetic spores of 

 plants with blastomeres of animals can be maintained in the light ot 

 all the modern nuclear physics with which I am acquainted and the 

 view here taken does away with the necessity of assuming a my- 

 sterious antithetic alternation in animals. 



•29* 



