272 



NATURE 



[December 28, 191 1 



CONSTRUCTIVE BIOLOGY. 

 Some Neglected Factors in Evolution: an Essay in 

 Constructive Biology. By H. M. Bernard. Edited 

 by Matilda Bernard. Pp. xxi + 489. (New York 

 and I.ondon : G. P. Putnam's Sons, 1911.) Price 

 I2S. 6d. net. 



MANY who know the late Mr. Bernard's work 

 in other fields— notably on Madreporarian 

 v,)i;ils, the .Vpodidae, the Galeodidae, and the retina- 

 will be interested in this essay in constructive biology. 

 Mr. Bernard was marked by a resolute independence 

 of thouf^ht, and this quality, strengthened by his 

 mathematical and philosophical training, is conspicu- 

 ous in the book before us, a posthumous work, very 

 carefully edited. 



The first part of the volume is an exposition of the 

 ])rotomitomic theory, according to which what arc 

 called "cells" are merely form-features of some 

 deeper underlying texture, namely, a fundamental 

 linin-chromatin network. In the retina of vertebrates 

 the author found a continuous network with the 

 nuclei at the nodes. He called this fundamental 

 reticulum in living substance, "the protomitomic 

 network." "The connecting filaments were seen 

 to be continuations of the filaments within the 

 nuclei, so that the latter appeared to be merely special 

 tangles of the filamentous network." In some tissues 

 a large amount of cytoplasmic matter is required for 

 their activities, and this tends to obscure the essential 

 reticular structure; in other tissues the filaments are 

 the most obvious structural elements. According to 

 Mr. Bernard's view, which is expounded in a tem- 

 perate, scholarly, and ingenious argument, the bio- 

 logical unit — both morphological and physiological — 

 is not the cell, but a node in the reticular linin- 

 chromatin system, a stellate linin-chromatin mass from 

 which filaments radiate. By concentration of 

 chromidia {i.e. minute chromatin particles which occur 

 in the nodes of the linin network), rearrangement of 

 filaments, and progressive centripetal differentiation, 

 and the like, the first cells may have arisen. They are 

 like enlarged editions of the chromidial units, capable 

 of a larger "life." 



This is not the sort of theory that can be called 

 right or wrong ; the question is whether it is useful 

 in the interpretation of cellular structure and function. 

 In a series of chapters the main conception — of a con- 

 tinuous filamentous system with nuclei distributed 

 as centres of functional activity — is cleverly used as a 

 key, not only in regard to structural details of 

 epidermis, nervous system, sense organs, and the like, 

 but also in regard to growth, cell-division, and even 

 heredity. We come at length to the idea that organ- 

 isms differ from one another in the pattern of their 

 protomitomic networks, which is like the morpho- 

 logical side of Haeckel's idea that organisms differ 

 from one another in the rhythm of their minutest 

 protoplasmic particles or plastidules. It is indeed a 

 fundamental biological conception that an organism is 

 an individualised persistence of a specific activity in- 

 separably associated with a specific structure. 



In many of the cells that we are in the habit of 

 looking at we are bound to confess that we cannot see 



NO. 2200, VOL. 88] 



anything of the protomitomic system, and the descrip- 

 tions given by some of the most expert cytologists are 

 not in favour of the author's view, which is essential 

 to his whole theory, that the filaments of the nuclear 

 network are cotitittuous with the network of the cell- 

 bodv. The suggestion is made that the use of osmic 

 acid is to blame for the modern denial of the unity 

 of the reticulum. Apart from the idea of continuity, 

 it is possible to find in many recent researches some^ 

 corroboration of the author's emphasis on the extra- ^ 

 nuclear chromatin. We think, for instance, of the| 

 modern insistence, due ver>' largely to Richard Hert-^ 

 wig, on the importance of the chromidial (i.e. extra-: 

 nuclear chromatin) apparatus in the cytoplasm. Or 

 we recall the " plastosomes " of Meves, elementary 

 structures in the cytoplasm, which are regarded as 

 the foundations or primordia of ontogenetic differen- 

 tiations. 



The second part of the book contains the author's 

 theory of evolution. It is very interesting, character- 

 istically fresh and independent, but within the space 

 at our disposal we cannot do more than allude to three 

 of its outstanding features. The first is the idea of a 

 cosmic rhythm, which is akin to a suggestion that 

 Herbert Spencer made, but left undeveloped, that 

 "life on the earth has not progressed uniformly, but 

 in immense undulations." As Mr. Bernard expressed 

 it : " Organic life is seen advancing out of the dim 

 past upon a series of waves"; period succeeds 

 period, each with a higher unit — "each evolutionary- 

 period can be described by the same formula, the 

 processes in all cases being essentially the same. 

 although the factors involved become increasingly 

 complex." The first period is that of the chromidial 

 unit, the second that of the cell unit, the third that 

 of the gastraeal unit, the fourth that of the annelidan 

 unit, the fifth that of man. One must remember, of 

 course, that even so far back as the Cambrian life 

 had got a long way past the simpler ex— ^^ ='^"': 

 of the annelidan unit. 



The second outstanding feature is the author s con- 

 viction that the Darwinian theory accounts for detailed 

 adaptation rather than for great advances in type. 

 and that the production of new types is describable as 

 a kind of colony-formation. This was the lesson that 

 the author learned from his thirteen years of work on 

 corals. "The physical force of life" has had periodic 

 outbursts of growth leading to the production of 

 homogeneous aggregates, to repeated colony- forma- 

 tion, to "raisings of the level of life," to "altogether 

 new organisation." Many naturalists have pondered 

 over colony-formation, and we are not prepared to 

 accept the statement on p. 299, that "colonies are 

 regarded by them merely as accidental knots in the 

 evolutionary chain, of no value to the chain." We 

 feel sure, for instance, that the veteran zoologist of 

 Jena will heartily agree with the thesis which his 

 esteemed student has developed in chapter xvii., that 

 colony- formation is an essential factor in evolution. 

 What we miss, however, is a recognition of alternat- 

 ing periods of aggregation and integration. 



The third distinctive feature in the etiology of this 

 book is the recognition of "a psychic element in life." 

 While " the assumption of a special ' vital force ' is a 



