962 LIFE : OUTLINES OF GENERAL BIOLOGY 



that this is indispensable, for self-fertilisation readily occurs, both 

 in the garden varieties and in the wild species of snapdragon. 



We get a vivid glimpse of "instinct" when we see a young Humble- 

 bee, perhaps on its first foraging expedition, tackle a difficult flower 

 like Antirrhinum. Only instinct would prompt a creature to try a 

 closed door and to lean its weight against it the very first time and 

 without any awkwardness. 



Since this century began there has been an intense study of 

 snapdragons on the part of botanists, and one of the keenest of 

 observers and experimenters has been Prof. Erwin Baur of Berlin, 

 who has devoted twenty years to studying variation and heredity 

 in the common species and its relatives. There are several reasons 

 why the snapdragon is well suited for this kind of inquiry. As we 

 have said, it is in a mutating mood; it is at present a copious foun- 

 tain of change. Moreover, it is a vigorous plant, not short-lived, not 

 difficult to cultivate, and a single blossom may have as many as 

 400 seeds. And the fact that it readily self-fertilises is of consider- 

 able advantage in genetic experiments, since it removes the com- 

 plication of dual parentage. 



What Prof. Baur has proved is very interesting, for, as regards 

 snapdragons, it brings us back to very orthodox Darwinism. The 

 garden races, which are almost entirely the differentiated descen- 

 dants of the wild species, are constantly exhibiting small mutations; 

 that is to say, intrinsic germinal variations, small in amount, but 

 crisp and brusque in character, and transmissible in their entirety 

 in Mendelian fashion. They have nothing to do with minute modifi- 

 cations imprinted on the individual by some pecuHarity of soil or 

 weather; for the small mutations are intrinsic, not extrinsic, out- 

 comes not imprints; and they are conspicuously transmissible or 

 continuable, which one dare not say of modifications or acquired 

 characters. The small mutations of snapdragons are expressions of 

 germinal changes in the hereditary factors; and they are probably 

 of the same nature as the large mutations or discontinuous varia- 

 tions, popularly known as sports or freaks. But they are small in 

 amount and of very frequent occurrence. 



Various evolutionists who admit the reality of mutations have 

 been inclined to depreciate their importance, on the ground that 

 they tended towards monstrosities and represented a weakening of 

 germinal vigour. This may be true in some cases, such as fancy 

 goldfishes or waltzing mice; but it is certainly not true of Baur's 

 small mutations in snapdragons, for these are generally new depar- 

 tures within the limits of normality. They find expression not only 

 in the flower and its colour but in many parts and characters of the 

 plant. Sometimes they suggest an enhancement of vigour, as when 

 a mutant appears with a deeper green in its leaves. In any case there 

 is rarely any hint of the pathological in the small mutations proved 



