LI>-XEA^' SOCIETY OF L0XD02f. 43 



the sperm-threads, both of which are equivalent io nuclei, and 

 probably ai*e characterized chemically by the so-called Kucleiii. 

 By the conjugation of one of these male and one of these female 

 nuclear structures arises the first nucleus of the new creature, 

 which is therefore to be regarded as a hermaphroditic formation, 

 and appears as carrier of male and female characters. From this 

 lirst embryonic nucleus all nuclei of the perfected creature are 

 derived in iin interrupted succession, and these therefore are 

 likewise representatives of both the generating organisms. 

 Through special operations of their minutest constituent particles, 

 the nuclei condition first the phenomena of multiplication of 

 the cells, and secondly their growth in volume and quality. 

 Typical conformations of particular organs and complete organisms 

 are the result of definite combinations of cell-diA isions and pro- 

 <:esses of cell-growth, and therefore the nuclei, by means of their 

 typical forces derived from the generative elements, dominate the 

 whole constituent process of the organisms, or, in one word, the 

 inhei'itance. 



In agreement with his friend Xiigeli's views as to the vegetable 

 kingdom, Koelliker believed in a polyphyletic origin for the 

 animal kingdom. He did not accept Ontogeny as any guide to a 

 general Phylogeny, arguing that the stages of development in one 

 group of creatures might recapitulate the genealogical history of 

 that group, without in any way proving its relationship to other 

 groups. He courteously but emphatically explains his attitude 

 of opposition to Darwin, Haeckel, and Weismann. To the 

 manifolding of organisms through the natural selection of favour- 

 able variations, he opposes his own idea that " the origin of the 

 whole organized world is to be accounted for by a great plan of 

 evolution continually driving on the simpler forms to more and 

 more diversified developments." There is something unsatisfying 

 in a doctrine which seems to say that the world has been evolved 

 by a plan of evolution which evolves it. But naturally the acute 

 professor has much to say to make bis opinion wear an air of 

 plausibility. For those who advocate a whole forest of genea- 

 logical trees in ])lace of one grand many-branching stem, there is 

 at least this to be said. Any complete and self-consistent theory 

 of evolution must surely have its basis, not in spontaneous 

 generation, but in some orderly transition from the inorganic to 

 the organic. That the requisite conditions for this should have 

 occurred only at one point of time and one point of space, and 

 have produced only one or two organisms, is not on the whole 

 very probable. Nature works with so much affluence that very 

 rarely does any known thing prove in the end to be really rare. 

 "When the undiscoverable is discovered, one expects soon to hear 

 that the new rarity is in fact freely disseminated through the 

 universe. It is quite conceivable that in jjast ages countless 

 specimens of the simplest organic type were produced and that 

 they are still being produced, but none the less all chance of 



