Febkuaky 5, 1904.] 



SCIENCE. 



223 



book, is the total absence of treatment of 

 vitalism, which, as all admit, has become too 

 troublesome a specter to be ignored in prob- 

 lems of adaptation. Eegrettable is this omis- 

 sion, none the less, since there are few authors 

 in a better position than Morgan to summarize 

 the strongest arguments of the neovitalists. 

 Altogether the book would have been more 

 valuable, it seems to me, if the author had 

 readjusted somewhat his themes; he might 

 thus have included a discussion of vitalism, 

 amplified his section on Naegeli's ' perfecting 

 principle,' and given a more adequate account 

 of orthogenesis, respects in which the work is 

 not to be mentioned in terms of Plate's, and 

 by the same token abridged his discussion of 

 natural and artificial selection. As it stands, 

 the work gives page after page quoted from 

 Darwin — indeed, throughout the entire book 

 there are over a hundred pages in quotation 

 marks. This extended treatment of the classic 

 aspects of selection, we freely admit, led us to 

 the false hope that the newer theme of organic 

 selection, as set forth by Osborn, Lloyd Mor- 

 gan and Baldwin, would at least be given 

 definite reference. 



As already remarked, each reviewer of a 

 work of the present broad scope will find 

 abundant ground for criticism. The most 

 formidable and most pertinent discussion 

 might easily arise over mutations themselves. 

 Morgan, like Korschinsky and De Vries, holds 

 that mutations are saltations by which new 

 ' modes ' are established in organisms, while 

 variations, in the sense of the usual selection- 

 ist, are changes occurring about the same 

 ' mode.' But we find that Morgan is willing 

 to go further, and embrace under the term 

 mutation all discontinuous variations. And 

 if this point is granted, I confess that I can 

 not see that his standpoint is widely different 

 in esse from that of the rank and file of latter- 

 day selectionists. Tor after all discontinuity 

 in variations is a question of degree, and it 

 would not be a serious matter to show that 

 transitions occurred between discontinuous to 

 continuous variations. A case, one which I 

 happen at the present moment to be interested 

 in, occurs in the development of Chirncera. 

 In the fertilization of this form supplemented 



spermheads, as they pass into the egg, divide 

 at once amitotically. And we have thus what 

 appears at first sight a distinct saltation from 

 the usual conditions in polyspermy. Com- 

 paring, however, Ckimwra with the conditions 

 in the allied sharks, we find that this peculiar 

 behavior of the sperm nuclei is not a feature 

 which has arisen as a discontinuous variation; 

 it represents nothing more nor less than an 

 abbreviated process of what occurs in the more 

 primitive sharks; in these forms amitosis in 

 sperm nuclei appears at the end of a graded 

 series of nuclear divisions, a series at one end 

 of which mitosis occurs, and at the other ami- 

 tosis. In the development of Chirncera the 

 earliest stage of the sperm nucleus thus cor- 

 responds to a late stage in the sperm nucleus 

 of sharks, and thus we conclude that the dis- 

 continuous character in Chirncera is not a new " 

 ' mode,' but a modified phase of a simple con- 

 tinuous process. This example, be it under- 

 stood, occurs not immediately between off- 

 spring and parent, but, like ' mutations ' in 

 paleontology, between offspring and early an- 

 cestor, but it seems to me that a typical mu- 

 tation differs from it in degree rather than in 

 substance, and that similar processes may com- 

 bine to form the complex of wonderfully ad- 

 justed discontinuous variations which we call 

 a typical mutation. I incline to the belief 

 that, in the elaboration of the doctrine of mu- 

 tations, Morgan, like some other transnautation- 

 ists,* keeps too prominently in the foreground 

 not the strands which make up the compli- 

 cated web of adaptation, but the mutant as a 

 whole, picturing not the few details of struct- 

 ure which our present knowledge enables us 

 to grasp, but a progression of brilliant, per- 

 fectly formed organisms, delicate in internal 

 adjustments and new, different from their 

 parents, indeed, even from their earliest 

 stages, a picture which, as Morgan says of 

 ISTaegeli's progression ' has a grandeur that 

 appeals directly to the imagination.' On the 

 other hand, admitting that discontinuous vari- 



** Morgan substitutes ' transmutation ' for ' evo- 

 hition,' adjusting the term more closely, therefore, 

 to his interpretation of the process. If terms are 

 to be shifted, why should not the Lamarckian 

 ' transformism ' be revived? 



