1894. SOME NEW BOOKS. 375 



But in drawing his contrast between the continuity of the 

 environment and the discontinuity of species, Mr. Bateson attaches 

 a curiously limited meaning to the term environment. It is quite 

 true that in the same spring weather, in the same fields, and on the 

 same flowers, lady-birds differing in striking but apparently unim- 

 portant details may be found, and side by side under the same 

 stones dimorphic earwigs occur. No doubt such instances could be 

 multiplied almost indefinitely wherever observers so careful as Mr. 

 Bateson are at work. But can we deduce from such facts as these 

 the necessity of abandoning continuity in the modification of species ? 

 If there is a struggle and a selection of the more favoured individuals, 

 there are a thousand elusive factors in the environment that may be 

 determining the existence of the animals. A slight difference in the 

 power of resisting bacteria, a change in physiological habit that 

 would write no mark upon the visible form of the creatures, and many 

 another factor overlooked by us, might well be the determining 

 cause of the animal's existence. These, no doubt, are all hypotheses, 

 but it is not a hypothesis to say that Ave are too ignorant of the 

 relations of any animal or plant to its environment to conclude that 

 discontinuous forms of life arise or exist in a continuous environment, 

 and therefore to seek explanation in discontinuous factors. When, 

 moreover, one remembers that each animal or plant is an organic 

 whole, and that selection of an invisible character must bring with it 

 selection of many visible characters, it is plain enough that, although 

 the characters which arrest our attention bear no intelligible relation 

 to what we know of the environment, we need not abandon old 

 methods and known causes to seek new and unknown causes. 



Turning now to discontinuity in variation, it is to be noted that 

 Mr. Bateson himself explains again and again that what he calls 

 discontinuity is merely a necessary result of growth, or of chemical 

 constitution. An embryonic cell divides, or it does not divide, and 

 there results in the adult two organs or one organ, but not one and 

 a half. A pigment is chemically altered, or it is not chemically 

 altered, and there results a new colour, or the old colour, but not a 

 series of intermediate shade. Such instances, however valuable as 

 part of existing nature, do not, however, so much as touch the 

 every-day instances of slight gradation and undoubtedly con- 

 tinuous variation that are to be observed in the shape and size 

 of various parts. Moreover, as Mr. Bateson himself is careful 

 to note, no adequate evidence is yet forthcoming with respect to 

 the inheritance of discontinuous variations. In short, what Mr. 

 Bateson has really done in his most interesting book is to collect 

 and formulate a large amount of information about the laws 

 of growth. He has shown clearly what naturalists are accustomed 

 to neglect. The body of any animal or plant forms an organic whole. 

 The various organs and structures are correlated together just as 

 physiologists have shown that the various functions of the body are 

 correlated together. In the case of physiological facts, there is as yet 

 little guidance for us in attempting to understand how the correlations 

 are affected. Mr. Bateson has shown how, in many cases, the 

 structures that build up the symmetrical organism are correlated ; 

 he has brought out clearly the most striking fact that variations 

 are not irregularities, but that they are as regular, and as har- 

 monious, as the ordinary conditions of organisation. Indirectly, this 

 will no doubt serve to explain the apparent discontinuity in species 

 by showing that, as Mr. Bateson says, the integral stages by which 



