PREFACE 



This book is intended for those who have read, or are reading, 

 Gray's Experimental Cytology, Heilbrunn's Outline of General 

 Physiology, Fruton & Simonds' General Biochemistry, Hober's 

 Physical Chemistry of Cells and Tissues and similar textbooks. The 

 subject is the life of the egg from the attachment of the fertilizing 

 spermatozoon to the fusion or apposition of the male and female 

 pronuclei. This process, except in mammalian eggs, usually takes 

 a little less than one hour. Even so, several important subjects have 

 had to be omitted: some of these are: (i) Fertilization in the decapod 

 Crustacea and in sponges. Both of these are too far removed from 

 'normal' fertilization to be included in a comparatively short book ; 

 but there are excellent accounts of them by Bloch (1935) and Tuzet 

 (1950). (2) Asters and the origin of the first cleavage amphiaster. 

 Much has been written recently on these, apart from the relevant 

 sections in some of the textbooks mentioned above. (3) Andro- 

 genesis and Gynogenesis. (4) Merogony. (5) Parthenogenesis. A 

 comprehensive review of parthenogenesis has been published by 

 Tyler (19416); but reference to the General Index will show that 

 the subject is occasionally mentioned. (6) Fertilization in the plant 

 kitigdojn. Although two chapters are devoted to this subject, its 

 treatment is far from systematic. 



The scope of this book precludes any discussion of cleavage, 

 which is frustrating; not only because cell division is such a 

 dominatingly important subject, but also because important papers 

 such as Brachet's Constitution anorniale du noyau et metabolisme de 

 Vemhryon chez les Batraciens (1954) cannot be considered. 



References. Modern reviews sometimes consist mainly of a list 

 of papers with little or no attempt at evaluation. Even if this 

 practice served some useful purpose it would be inappropriate in 

 a short book. The papers referred to represent a limited selection 

 from the immense number on fertihzation written during the last 

 hundred years and, as a rule, I have excluded the following: (i) 

 references to work which has recently been repeated, under more 

 modern conditions. But attention is sometimes called to early 

 papers on subjects in which there has been a revival of interest, 

 such as cortical granules and the effect of calcium on the hardening 



