1894. SOME NEW BOOKS. 139 



in modern scientific pamphlets — the references to all the writers 

 mentioned are pleasant and appreciative. Starting with the discovery, 

 in August, 1677, of spermatozoa by Leeuwenhoek's pupil, Hamm, 

 the writer traces the gradual advances in knowledge which have led 

 to our modern conception of the sexual cells in animals and plants. 

 He shows the general parallelism existing between animals and 

 plants in respect both of the sexual cells and of the male and female 

 organisms containing them. He shows how, in both, the male cells 

 become adapted to reach the usually larger and more passive female 

 cells, and how the sexual characters of the male and female organisms 

 are adapted in association with these diverging capacities. He 

 touches lightly upon the determination of sex, the influence of 

 crossing, and of in-and-in breeding and kindred topics. We recom- 

 mend this book readily — not to biological specialists, who would find 

 in it nothing very new, but to anyone who wishes an agreeable and 

 instructive hour's reading. 



Biological Homilies. 



Biological Lectures and Addresses delivered by the late Arthur Milnes 

 Marshall. Edited by C. F. Marshall. 8vo. Pp. viii. and 363. London : 

 David Nutt, 1S94. Price 6s. 



" Homilies," says the Judicious Hooker, " are plain and popular 

 instructions." Justly, then, may we apply this term to the essays 

 comprised in the present volume. The exposition of the advanced 

 teachings of modern biology in language that shall be lucid yet not 

 misleading, intelligible yet not inaccurate, increases in difficulty with 

 the increase and extension of knowledge itself. Along whatever path 

 of zoological specialisation we proceed, we are speedily confronted by 

 a bristling array of technical terms, erected as necessary waymarks 

 for the pioneers themselves, but presenting a well-nigh impenetrable 

 barrier to their merely curious followers, while they are also 

 unintelligible to their fellow workers on other paths. We, who 

 month by month endeavour to lay the results of special research in an 

 intelligible form before our readers, well understand the difficulties 

 of such a task, and readily appreciate how successfully they have 

 been overcome by the enthusiastic biologist whose loss we still so 

 deeply mourn. 



Most of the lectures contained in this book are reprinted from the 

 Transactions of the Manchester Microscopical Society or from other publica- 

 tions. Five, however, are now printed for the first time from such 

 manuscripts as were left in a fit state. These five were mostly 

 delivered thirteen years ago, and include " The Modern Study of 

 Zoology," " The Influence of Environment on the Structure and 

 Habits of Animals," "Embryology as an Aid to Anatomy," "The 

 Theory of Change of Function," and "Butterflies." The remainder 

 deal chiefly with Cell-division, the theories of Weismann, experi- 

 mental Embryology, and above all with the Recapitulation Theory, 

 which indeed is a regular King Charles's head. 



The merit of these addresses is to be found rather in their clear 

 and vivid style than in any great originality of idea. Perhaps the 

 earlier pages have occasionally too strong a platform flavour, which 

 the author himself would probably have edited out. In other respects 

 the volume contains admirable models for the populariser of biology, 

 refreshing reading for the amateur scientist, and reliable synopses for 

 those whose special studies have not left them time to follow the 

 intricacies of other branches than their own. 



