1893. SOME NEW BOOKS. 463 



plexity of the observed phenomena of which it is the abstraction 

 necessarily will seem artificial. To those who are inclined as they 

 read these lines to cry out on the artificiality, I can only say — work 

 through Weismann's application of his theory and see what a master 

 key it seems to the confused tangle of life. 



While at first sight this theory seems to present only a formal 

 simplification of the facts of heredity, inasmuch as it seems to put on 

 the biophor the whole mystery of life, I am inclined to think that this 

 objection is not valid ; for if the mechanical marshallings and evo- 

 lutions and devolutions of the biophor and its higher aggregations do 

 actually form a picture in little of the larger complexities of the visible 

 world, we can at once remove from the problems to be solved these 

 actual complexities. We shall, in fact, by W^eismann's help, effect a 

 separation of those problems of living material which are functions 

 of the complexit}' of organisms and not actual difficulties of living 

 matter itself; and those who are familiar with the recent advance in 

 our knowledge of the elaborate marshallings and evolutions and devo- 

 lutions of the chromatin in dividing nuclei, can hardly say that Weis- 

 mann's postulated movements of the elements of the germ-plasm make 

 a large demand on credulity; but this depends upon our being able to see 

 clearly that the mechanism is a possible one. I freely admit that 

 as yet I have not assimilated Weismann's book sufficiently to follow the 

 clear image that is obviously present in his mind. He expressly 

 states that he has felt the difficulties in giving up an epigenetic view 

 of ontogeny. 



It will be seen that, leaving out the foregoing considerations, we 

 are led up to the ultimate problem in the biophor. That is really the 

 problem of assimilation, and is the factor as yet unexplained in any 

 theory of biology. The possible migration of biophors from the 

 nucleus to the protoplasm usefully shifts the problem of "fern- 

 wirkung" (the translator rather unhappily renders this " emitted 

 iniiuence," instead of the obvious "action at a distance") to the 

 protoplasm itself. When we understand how protoplasm can feed 

 and grow, we shall probably have little trouble in understanding 

 the nucleus. 



P. C. M. 



The Microscope : Its Construction and Management. Including Technique, 

 Photo-Micrography, and the Past and Future of the Microscope. By Dr. Henri 

 Van Heurck. English Edition. Translated by Wynne E. Baxter, F.R.M.S., 

 F.G.S. With plates, and upwards of 250 illustrations. London and New 

 York : Crosby Lockwood & Son, 1893. 



The English microscopist has, for at least a generation, shown that 

 he is sufficiently in earnest to be cosmopolitan. He can welcome 

 warmly good English work, in either the manufacture or the use of 

 the microscope, or in the excellence of a treatise on its principles and 

 application. But there is definite evidence that he has learned to 

 prefer the quality of an instrument or a handbook to its source. In 

 fact, there is danger that the foreign maker, having obtained by 

 sheer excellence and moderate prices an assured position in this 

 country as the producer of the principal optical elements of the 

 microscope, that the prejudice runs wholly in favour of instruments 

 of foreign production, to the sacrifice of much that is of really higher 

 excellence made in this country. 



