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 Weismann’s help, effect a 
separation of those problems of living material which are functions 
of the complexity 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 
alargedemand on credulity; but this depends upon our being able tosee 
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 probiem 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 
influence,” 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. 
Paine 
Tue 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. 
Tue 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. 
