REVIEWS 367 



said to make it clear that this is a book which will need to be in every botanical 

 library, while at the same time its interest for the organic chemist and bio- 

 chemist is very great indeed. 



J. H. P. 



Heredity and Sex. Columbia University Lectures. By Thomas Hunt Morgan, 

 Ph.D. [Pp. ix + 282.] (Columbia University Press, and Humphrey 

 Milford, London, E.C., 1913. Price 7s. 6d. net.) 



Prof. Morgan, like many other biologists, has been impressed by the great 

 advances that have been made in recent years along two lines of research. The 

 study of the cell has been pursued by a multitude of observers : errors of observa- 

 tion and interpretation have been corrected, and a clear and tolerably coherent 

 picture is being gained as to the nature of nuclear changes, the normal chromo- 

 some contents of different types of cells, and the events of maturation, formation 

 of polar bodies, and fertilisation in the case of the sexual cells. The experimental 

 study of inheritance has occupied even a larger number of acute observers, with 

 the result that a most important body of knowledge has been gained as to the 

 particulate nature of inheritance, the fashion in which the units are transferred, 

 combined, remarshalled, segregated, or linked. The former set of observations 

 shows the existence of an elaborate machinery for the segregation, distribution, and 

 reassembling of the physical substance which most of us now believe to be the 

 hereditary material. The latter set of observations would seem theoretically 

 to demand the existence of a complex and particulate machinery. Prof. Morgan 

 thinks that "a failure to recognise the close bond between these two modern lines 

 of advance can no longer be interpreted as a wise or cautious scepticism." The 

 task that he has set himself is to show in as much detail as possible that there 

 is a close and suggestive correspondence between the two sets of results. 

 Unfortunately most of the points that he discusses can be interpreted in different 

 ways, and we are not prepared to go farther than to commend his book as 

 stimulating and useful. 



Artificial Parthenogenesis and Fertilisation. By Jacques Loeb. [Pp. x + 

 312.] (The University Press of Chicago ; The Cambridge University Press, 

 London, 1913. Price 10s. net.) 



This volume was originally translated from the German edition, but has been supple- 

 mented and revised by the author and now gives a clear and connected account 

 of the extraordinarily novel work that Professor Loeb has been carrying out. When 

 it first became known that he had succeeded in fertilising eggs by chemical 

 agencies, it seemed as if the discovery were too remote from what was known to 

 be true. In the Introduction, however, he gives an explanation which brings the 

 results of his experiments, however surprising, into line with other work. The 

 spermatazoon has a double function. It transmits paternal characters to the 

 developing embryo and this function cannot be replaced by physical agents. 

 But it also excites the development of the egg. The latter action is not specific, 

 for the eggs of the sea-urchin can be fertilised with the spermatazoa of quite 

 different genera and species, e.g. starfish, brittlestars, holothurians, crinoids, and 

 even molluscs. In these cases the developing embryo reproduces only the 

 maternal characters, and it is this action that can be replaced by physical 

 stimuli. 



Both the spermatazoon and the physical agents with which it may be replaced 



