894 



SCIENCE 



[N. S. Vol. XXXI. No. 806 



cultivated a long time before sporting is 

 induced, and that in any case sports are 

 actually or relatively very rare. Will 

 these ideas stand the test of scientific 

 scrutiny experiments? It is evident that 

 these problems are of high importance 

 both to evolutionists and to agriculturists. 

 De Vries with his (Enotheras and his 

 theory of mutation as the chief factor in 

 evolution has particularly interested the 

 scientific world in these phenomena. He 

 has worked out in great detail the facts 

 of variation as they occur in the evening 

 primrose and makes a strong case for his 

 theory. Recent cytological study of the 

 CEnothera mutants or variants shows that 

 one of them has twice as many chromo- 

 somes as the others; in other words, that 

 this mutant at least has suffered a pro- 

 nounced change in its hereditary mech- 

 anism. It is only natural that this should 

 at once have aroused the suggestion that 

 perhaps all sports or mutants are the re- 

 sult of more or less marked derangement 

 of the hereditary mechanism, by which a 

 character or factor of some sort is gained 

 or lost. MacDougal's work in subjecting 

 very young ovules to chemical infiuences, 

 and Gager's similar experiments with 

 radium emanations, are also reported to 

 have yielded marked variations, perhaps 

 sports. Tower also secured true sports in 

 increased numbers from his Colorado 

 potato beetles by subjecting them to un- 

 toward conditions of heat and moisture 

 during breeding. In this case, however, 

 all the sports secured were previously 

 found occurring naturally. There is a 

 tempting subject here for speculation— 

 indeed one that has been assiduously 

 tiUed, but to foUow it up will lead us 

 too far afield. The limited historical 

 and experimental evidence of a critical 

 character clearly upholds, however, the 

 reality of sports. 



It is an illuminating fact that most of the 

 information concerning the origin of culti- 

 vated plants and animals is that brought 

 together long ago by Darwin. Recently 

 De Vries has gathered much additional 

 data. Both these men sought the facts 

 primarily in support of a theory. Scien- 

 tific men are usually more concerned in 

 finding an explanation of phenomena than 

 in gathering the facts. But we can not 

 all be philosophers and theorists— indeed, 

 the principal difficulty with biological 

 science is that we have a plethora of 

 theory and a dearth of critical facts. Es- 

 pecially is this true in the subject of bio- 

 logical evolution, where nearly every pos^ 

 sible guess and combination of. guesses as 

 to the actual method of evolution has been 

 made. Where such guesses or theories 

 stimulate additional inquiry they are val- 

 uable—otherwise, they are useful only to 

 practise mental gymnastics. It is the 

 great merit of many recent investigators, 

 De Vries in particular, that they empha- 

 size the importance of experimentation. 

 De Vries 's work bristles with suggestive 

 lines of experimentation mostly bearing 

 on the subject of the origin of cultivated 

 plants, and nearly all of practical impor- 

 tance in agriculture as well of great in- 

 terest in themselves. If any one believes 

 that there is any immediate likelihood of 

 biologists agreeing on evolution, all he has 

 to do, using the slang of the day, is to 

 start something. However much agree- 

 ment there may be on the facts— there is 

 sure to be violent disagreement on the in- 

 terpretation of the facts. For example, 

 De Vries and others believe that sports 

 which usually breed true from the start 

 are intrinsically different from ordinary 

 or fluctuating variations induced by soil 

 or otherwise and which have no effect on 

 the offspring. On the other hand. Tower, 

 who has conducted extensive investiga- 



