Preface 



A quarter of a century has passed since the first edition of this 

 book was pubHshed. During that period cytology has been 

 transformed. Seldom has any branch of science been so revolu- 

 tionized in a similar period by the invention of new techniques 

 and the revival of old ones. The subject-matter of the Cytological 

 Technique of 1933 is only a little fraction of the cytological 

 technique we know today. Nevertheless, the old processes of 

 fixation, embedding, dyeing, and moimting survive and flourish. 

 Indeed, it seems probable that even hundreds of years hence they 

 will still be necessary. Perhaps some cytologist of the distant 

 futiire, looking through the books on a forgotten shelf in the 

 basement of an old library, will read these words and agree that 

 I was not mistaken. 



The old title of the earlier editions is retained at the special 

 request of the Publishers. The newer branches of the subject are 

 being covered in Biological Monographs written by other authors. 

 Dr W. G, B. Casselman's book on Histochemical Technique^^ has 

 already been published, and another by Dr J. Chayen on bio- 

 physical methods is in course of preparation. 



The earlier editions have been subjected to the sincerest form 

 of flattery, for considerable parts have been taken from them 

 and reprinted in text-books with scarcely any change, and usually 

 without acknowledgement; and the Chinese have done me the 

 honour of pirating the whole book and producing it in their own 

 characters. All this is very encouraging and suggests that the 

 underlying plan was good. So, although this new edition has been 

 rewritten from start to finish, without the copying of a single 

 sentence, yet I have followed the original plan. That is to say, 

 I have chosen as few and as simple techniques as possible, and 

 have used them as illustrations of general principles. 



vii 



