i8 95 . INDIVIDUAL VARIATIONS. 3§7 



generally, all plants can become temporarily depauperised by 

 atrophy ; but if the poor environment be perpetual, then the variety 

 " depanpcvata" can become relatively "fixed," and is often recog- 

 nisable as such by systematists. 



As another class of variations in individuals, their aestivation 

 may be mentioned. If buds of Laurustinus, primroses, wallflowers, 

 etc., be examined, every variety of aestivation can be pretty well met 

 with in each. If aestivations, however, be constant, as in mallow, 

 then they become classificatory characters. Lastly, Mr. Scott Elliot 

 has given interesting statistics of the varying dimensions of leaves 

 due to varying amounts of illumination, etc. 5 



Now, all these comparatively slight individual differences, and 

 very many others that might be mentioned, arise, as it seems to me, 

 because no two organisms of the same species can grow with a mathematically 

 exact likeness ; so that the laws of growth and development of organic 

 beings cannot be compared with, say, gravitation and the laws 

 regulating the constant angles of crystals. 



As long, however, as wild plants are all growing together in the 

 same natural environment, such variations in one and the same 

 species, or in different flowers on one and the same individual plant, 

 do not amount to true varietal or specific differences in the eyes of a 

 systematist. Yet it is just out of these that Natural Selection is sup- 

 posed to make its choice ; but in point of fact it cannot do so. 



Though this statement may be opposed to the prevailing creed, I 

 think it is correct and in agreement with Mr. Wallace's statement 

 of such characters being " non-specific." Thus the writer in Natural 

 Science says (p. 218) : — " It may be taken for granted that most biolo- 

 gists agree that variations of a nature similar to those now occurring 

 among plants and animals have been the source of the differences 

 between the varieties, species, genera, and so forth, in which existing 

 animals and plants are classified." According to Darwin, such varia- 

 tions supply the materials for Natural Selection ; but observations do 

 not seem to me to support this view. The writer proceeds to observe, 

 and very rightly, that " the chief difficulty in [this] view is that it is 

 impossible to see in many cases, perhaps in any case, how small 

 variations could have a value in selection ; how, in fact, the gradual 

 increments in a continuous change could each have had a determining 

 value in the selection of the animal or plant." 



Let us test it by an example. Caltha palustris has itself no 

 recorded variety in low-lying situations; yet Mr. Cockerell 6 has been 

 able to enumerate a great variety in the number of carpels of plants 

 growing in one place, Corfe ; and, presumably — as it, at least, is 

 usually the case with Caltha — growing more or less crowded over 

 marshy ground. Notwithstanding all its variations, Natural Selection 

 appears to stand aside and to look upon all of the innumerable small 



""Jouvn. Linn. Soc. xxviii., p. 371, 1891. 

 6 Nature, March 21, 1895, p. 4S7. 



