76 



NA TURE 



[May 27, 1897 



more than an outline of the chief doctrines concerned, 

 it is the fact that there is no treatise in English or 

 German which contains so useful a review of biological 

 theory. Written as it is, with a patriotic motive — 

 namely, that of inducing the rising generation of French 

 zoologists to occupy themselves with the general theories 

 (such as those of Darwin, Wallace, Weismann, Spencer, 

 Naegeli, and others) which have, as he justly states, re- 

 ceived far more attention in this country and in Germany 

 than in France — the book should prove of very great 

 value also to English students. This is sufficient excuse 

 for now drawing attention to Prof. Delages' volume, 

 although it was published more than a year and a half 

 ago. So far as I am aware, it is not so widely known in 

 this country as it should be on account of its compre- 

 hensive and thoroughly interesting character. 



It is true that the preface to his work has caused some 

 disagreement among the Professor's own colleagues. M. 

 Delages in severe terms expresses his disapproval of the 

 old school of zoological and botanical studies. He points 

 out (and I think justly) that whilst French men of science 

 have taken a leading part in the development of biological 

 doctrine and methods of study during the century, yet 

 that there has been during the past twenty years in 

 France a tendency to " une fausse direction des re- 

 cherches biologiques." Yox works or memoirs of im- 

 portance bearing upon the great problems of general 

 biology, there are, says M. Delages, for every one 

 written in French, three in English and ten in German. 

 He attributes this to the fact that French students have 

 not had their attention sufficiently directed to these 

 great problems. Accordingly, by a very remarkable effort, 

 he has produced the present work which shall (and 

 in my opinion does) serve as a cyclopaedia of biological 

 theory, by aid of which the French student may be 

 introduced to this hitherto neglected field, and led to 

 study for himself original authorities. In fact Professor 

 Delages has, first of all by diligent study, corrected for 

 himself what he regards as the defect in the current 

 education of a French zoologist, and then has embodied 

 his valuable abstracts and critical notes in the volume 

 which he offers to the young men who come after him. 



In spite of the fact that there are others in France who 

 have recognised, as does M. Delages, the importance of 

 modern theories in biology as stimulating and directly 

 producing new observations, and thus building up the 

 fabric of biological science, yet, on the whole, I am con- 

 vinced that M. Delages is right, and that such a book as 

 his was needed and will be very fruitful in France. It is 

 so good a book that it will be of great service also in 

 England. 



It is true that M. Delages seems to have forgotten for 

 a moment, in speaking of the growth of histological tech- 

 nique as foreign to France, that Ranvier, of the College 

 de France, is one of the most original and fertile dis- 

 coverers in this field at present living. It is also true 

 that his colleague. Prof Alfred Giard, who is sur- 

 rounded by an enthusiastic band of disciples, has for 

 many years taken actually the same attitude as that 

 adopted by Prof Delages, and has proclaimed the im- 

 portance of the new theories, and insisted, not only by 

 precept, but by example, on the necessity of carrying on 

 observation and experiment in zoology in order to test 

 NO. 1439, VOL. 56] 



hypothesis, and to determine the truth or error of current 

 theory, rather than let them take the form of exact but 

 meaningless record of facts, pointing to no general conclu- 

 sion. None the less, it seems to me that Prof Delages' 

 contention is true, and that, in spite of brilliant exceptions, 

 biological science has too often followed a false direction 

 in France (and no doubt in England also), owing to an 

 ignoring of the great search-lights of theory which 

 happen to have originated outside France. The ten- 

 dency to which Prof. Delages alludes was sufficiently 

 obvious to those who were able to watch, as many still 

 alive did, the reception of Darwin's theory of the origin 

 of species by natural selection in France, on the one 

 hand, and in Germany on the other. There can be no 

 doubt that the publication of M. Delages' book is evi- 

 dence of the fact that what may be called " modern 

 biological theories " are now receiving due attention in 

 France, and that the brilliant originality and independ- 

 ence of thought, as well as honesty and ingenuity of 

 observation which characterise French men of science, 

 will more and more be directed to the solution of those 

 great problems which occupy the attention of the biological 

 world at large. 



A brief sketch of the contents of Prof Delages' 

 book is all that the space of this article permits me 

 to give. It is divided into four parts : Part i. The 

 Facts ; Part ii. Special Theories ; Part iii. General 

 Theories ; Part iv. The Theory of Actual Causes. 

 Under Part i. are treated (i) The Cell : its constitution, 

 its physiolog), its reproduction ; an admirable resum^ 

 in ninety pages of the recent work, both on karyokinesis 

 and the physiology of protoplasm. (2) The Individual : 

 regeneration, grafting, generation, ontogeny, alternation 

 of generations, sex and secondary sexual characters, latent 

 characters, teratogeny, correlation, death and continuity 

 of life, the germ-plasma. (3) The Race : heredity, varia- 

 tion, the formation of species. Under Part ii. we find 

 statements of the following theories, (i) Speculative 

 theories as to the structure of protoplasm and the cause 

 of its movements, viz. the theories of Berthelot, of Verworn, 

 of Quincke, and of Butschli ; (2) theories of cell-division ; 

 (3) theories of regeneration ; (4) of polar globules ; (5) 

 of sexual generation ; (6) of the ontogenetic process ; 

 (7) of the parallelism of ontogeny and phylogeny ; (8) of 

 the origin of sex ; (9) of teratogeny ; (10) of death and 

 of germ-plasma; (11) of heredity; (12) of the trans- 

 mission of acquired characters ; (13) of latent characters ; 

 (14) of telegony ; (15) of hybridity ; (16) of variation; 

 (17) of the formation of species. 



Under Part iii. we have statements and brief, but 

 trenchant, criticism of the theories of "animism," "evo- 

 lutionism" (spermatists and ovists), and "micromerism." 

 Under the last term are included and considered the 

 views of Buffon, Bdchamp, H. Spencer, Haacke, Dolbear, 

 Erlsberg, Haeckel, His, Cope, Orr and Maulia, and 

 many others, including that of "ancestral plasmas" 

 (Weismann), pangenesis (Darwin), stirpes (Galton), whilst 

 " organicism " is the term applied to the theory of 

 Descartes and to the auto-determination of Roux. 



In the fourth and last Part are given " Idees de I'auteur," 

 a retrospect and review of much of what has been already 

 treated at greater length, with the definite introduction of 

 the author's own conclusions. By this method of division 



