S8 



SCIENCE-GOSSIP. 



BOOKS TO READ 



Materials for the Study of Variation, treated with 

 especial regard to Discontinuity in the Origin of 

 Species. By William Bateson, M.A., Fellow of 

 St. John's College, Cambridge. 614 pp. royal 8vo. 

 Illustrated. Price £i is. net. (London and New 

 York: Macmillan and Co., 1894.) 



The fine work by Mr. Bateson, just issued by 

 Messrs. Macmillan and Co., is a first instalment, 

 and will undoubtedly stand as a way-mark on the 

 path to investigation of the origin of species. As 

 in one direction biologists have found a key to the 

 origin of species in the study of variation caused 

 by environment, so may a key be found to another 

 entrance to the knowledge by a study of casual 

 variation in animals and plants. In this book Mr. 

 Bateson has collected an immense mass of evidence 

 as to what are commonly called " freaks " of nature. 

 There are over two hundred illustrations, the 

 majority of which contain several independent 

 drawings, two of which figures we reproduce as 

 examples, by permission of the publishers. One is 

 of what may be called a "unicorn" roebuck, and 

 the other, cases of double operculum of whelks. 



The first eighty pages are devoted to an intro- 

 duction, which is in itself a treatise on variation, 

 worthy of separate publication. 



In his preface Mr. Bateson says : — 



"To collect and codify the facts of variation is, I submit, 

 the first duty of the naturalist. This work should be under- 

 taken if only to rid our science of that excessive burden of 

 contradictory assumptions by which it is so oppressed. 

 Whatever be our views of Descent, Variation is the common 



basis of them all Difficulty has hitherto arisen from 



the fact that Variation is not studied for its own sake. Each 

 observer has some other object in view, and we are fortunate 

 if he is good enough to mention in passing the variations he 

 has happened to see in following his own ends." 



that the various forms of organisms are very commonly 

 differentiated from each other. Their forms are classified 

 by all sorts of characters, by shape and proportions, by size, 

 by colour, by habits and the like ; but perhaps almost as 

 frequently as by any of these, by differences in number of 

 parts, and by differences in the geometrical relations of the 

 parts. It is by such differences that the larger divisions, 

 genera, families, etc., are especially distinguished. In such 

 cases of course the differences in number and Symmetry do 

 not as a rule stand alone, but are generally and perhaps 

 always accompanied by other differences of a qualitative 

 kind ; nevertheless, the differences in number and Symmetry 

 form an integral and very definite part of the total differences, 



1 ^TyI-vY 



Double opercula of Buccinum undatum. 

 Figs. I. and II. natural size. 

 In the part of Mr. Bateson's study of variation 

 now under notice, he deals with what he terms 

 merism, or meristic variation, as opposed to what he 

 terms substantive variation. The former he explains 

 as follows : — 



" As it is the fact, first that Repetition and Symmetry are 

 among the commonest features of organized structure, so it 

 will be found next that it is by differences in those features 



Roebuck with compounded horns. 



so that in any consideration of the nature of the processes by 

 which the differences have arisen, special regard must be 

 had to these numerical and geometrical, or, as I propose to 

 call them, Meristic, changes. . . . We have thus con- 

 stituted a group which is to include Variations in number, 

 division, and geometrical position. From these phenomena 

 of division may be distinguished Variations in actual con- 

 stitution or substance of the parts themselves. To these 

 Variations, the name Substantive will be given. . . . For 

 the present it will be convenient to constitute such a 

 temporary group in order to bring out the relative 

 distinctness of Variations which are Meristic." 



As an example of the difference between 

 the value of these two words, the author 

 says : — ■ 



" The flower of a narcissus is commonly divided 

 into six parts, but through Meristic Variation it may 

 be divided into seven parts, or into only four. Never- 

 theless, there is in such a case no perceptible change 

 in the tissues or substance. . . . On the other 

 hand, narcissi, for example, N. corbularia are known 

 in two colours, one a dark yellow and the other a 

 sulphur yellow, though the number of parts and 

 pattern of the flowers are identical. This is, there- 

 fore, an example of Substantive Variation." 



We have quoted our author somewhat 

 liberally to make these terms for different 

 forms of Variation clear to our readers. 

 Now that we have for the first time gathered 

 together, skilfully grouped, arranged and judicially 

 considered, a large number of freaks of nature, we 

 cannot fail to appreciate their value. We trust 

 that the issue of this remarkable work will cause 

 students to look with less contempt upon such 

 freaks as they meet with, and now that they know 

 of this form of Variation being systematically 

 studied, they will send either the specimens or 

 particulars to Mr. Bateson. 



