406 



SCIENCE 



[N. S. Vol. XLIII. No. 1108 



which contained within itself the whole range of 

 diversity which living things present. 



Man simply an unpacked amoeba! The 

 mammal but a released protozoan ! Amceba 

 proteus a Prometheus bound! Not only 

 the myriads of factors which represent 

 "the whole range of diversity which living 

 things present," but also the inhibitor for 

 each waiting to assist in the unpacking and 

 the thing that did the unpacking, all en- 

 compassed within the confines of a primor- 

 dial cell! Also an implied super-Mosaic 

 Diety that foresaw all this and did the orig- 

 inal packing. The good old Presbyterian 

 doctrine of foreordination absolutely out- 

 done at last! Regeneration in its original 

 theological sense biologically afSrmed! 

 And why not ? Since we are told that un- 

 ehastity in women is a unit character, 

 chastity is attained by the miraculous re- 

 lease brought about by an inhibitor that is 

 brought to a sense of its sinfulness and 

 abandons its wicked ways; and the poor 

 woman is started on the way to total sane- 

 tifieation ! 



Surely, we have now witnessed the ex- 

 treme swing of the pendulum along the 

 Mendelian path, and the reverse swing is 

 due. 



But no one will deny, all jesting aside, 

 that real progress has been gained by the 

 Mendelian swing, nor that this doctrine 

 has contributed a distinct advance in our 

 biological thinking. Few will fail to ac- 

 knowledge that the factorial hypothesis ex- 

 plains much that has been obscure; that 

 dominant and recessive are terms that will 

 endure; that mutation will solve many a 

 perplexing problem, possibly not of spe- 

 cies in a state of nature, but surely of va- 

 rieties under cultivation and of hybridiza- 

 tion. 



The idea of rhythm or swing has been in 

 the minds of many thinkers. It is at the 

 center of biological activities. Geddes and 



Thomson, in speaking of the historical os- 

 cillations between the mechanistic inter- 

 pretation of the living organism and the 

 vitalistic appreciation of it, say : 



Now it is a machine and again it is a spirit, now 

 an antomaton and again a free agent, now an 

 engine and again an entelechy. The pendulum of 

 thought continues to swing.- 



Numerous illustrations of this biological 

 rhythm will occur to each of us. Cell di- 

 vision and conjugation, medusa and hy- 

 droid colony, growth and reproduction, 

 anabolism and katabolism, life and death. 

 These are all swings of the pendulum. But 

 there is also a steady advance. The life of 

 the individual includes both swings, but 

 there is also a real advance in the complex- 

 ity of the species ; and from these advances 

 new species arise, whether by mutation or 

 by the accumulation of variations. 



The question as to what causes the ad- 

 vance will be answered when we at last 

 find the real cause of evolution itself. 



In contemplating this swinging and ad- 

 vancing pendulum of thought certain 

 fundamental principles of wide application 

 come to occupy the focus of attention : 



1. While the pendulum swings regu- 

 larly to right and left, it never actually re- 

 traces its course; but advances with each 

 swing. There is a net gain which records 

 definite progress, and this progress is, in 

 general, along the line of evolution. 



2. The extreme of each swing is actually 

 further away from the real path of prog- 

 ress than the mean, away from the main 

 direction of advance. The extremest is al- 

 most invariably wrong, in the main. He 

 lets his imagination run away with him and 

 carry him much too far, and the wise man 

 will not follow him, but stops far short of 

 the extreme and usually actually pulls 

 back. This is the really valuable service 

 of the conservative mass of thinkers in any 



2 " Evolution, " 1911, p. 202. 



