482 



SCIENCE 



[Vol. LV, No. 1427 



are eonvenient for conveyance but they have to 

 be soaked np before they are palatable. 



Edwin E. Slosson 

 Science Service 



Washingtox 



SCIENTIFIC BOOKS 



An Introduction to Cytology. By Lester W. 



Sharp. McGraw-Hill Book Company, New 



York, 1921. 452 pages, 159 illustrations. 



For a subject of such wide interest and 

 great significance as cytology, there are sur- 

 prisingly few text books. For years Wilson's 

 classic work, "The Cell in Development and 

 Inheritance," has been the chief reference vol- 

 ume, especially of the beginning investigator. 

 Very recently two English tests, one by W. E. 

 Agar, "Cytology, with Special Reference to the 

 Metazoan Nucleus," and another by L. Don- 

 caster, "An Introduction to the Study of 

 Cytology," have appeared. These are good 

 books, dealing in both cases, however, with a 

 rather limited field and largely with animal ma- 

 terial. There has long been felt the need for an 

 introductory text which would present an out- 

 line of the subject in both its botanical and 

 zoological aspects. The rapid advances made 

 by numerous investigators, working upon a 

 great variety of materials, and the intimate 

 relation of these in many cases to equally rapid 

 developments in the other new science of 

 genetics, have made the writing of a cytological 

 text book a very difficult matter. 



Professor Sharp, despite these obstacles, has 

 done an excellent piece of work for he not only 

 covers the fields of botany and zoology, bvit 

 embraces in his consideration of subjects most 

 of those necessary for an understanding of the 

 scope of cytological knowledge. Very properly, 

 however, he places emphasis upon the topics of 

 greatest general interest. We find, therefore, 

 that of the 452 pages of text, 240 are devoted 

 to the hereditary mechanism and the results of 

 its operation. Zoologists, particularly, will 

 welcome so comprehensive a summary of the 

 achievements of their botanical fellows as Pro- 

 fessor Sharp presents. While this is naturally 

 the strong part of the work, zoological material 

 is well considered. Indeed, the author deserves 

 special commendation for the completeness and 

 fairness with which the contributions of zoolo- 



gists are treated. In view of the general ex- 

 cellence of the book in this respect, it might be 

 permitted, in the interest of the accuracy for 

 which the author very evidently strives, to 

 point out that in a few cases he has allowed 

 his personal studies to influence his presenta- 

 tion of topics concerning which there are dif- 

 ferences of opinion. Perhaps the most con- 

 spicuous example of this is in the discussion 

 of the differential structure of the chromatin 

 thread. While there may be uncertainty on 

 this point in plant material, there is none in 

 many animal forms. 



The method by which the material is pre- 

 sented is entirely to be commended. In recog- 

 nition of the developmental stage of the sub- 

 ject. Professor Sharp has endeavored to set 

 forth its status by showing what the problems 

 are and how they are being met, rather than 

 by attempting to define in categorical terms 

 the content of our knowledge. The spirit and 

 motives of an investigation are as important as 

 its achievement, and, since cytology is now so 

 largely a matter of discovery, it would be a 

 misrepresentation to exhibit it otherwise than 

 as an active field of research. 



As practical measures for such a presenta- 

 tion it may be noted that the numerous illus- 

 trations are, almost always, copies of those 

 found in research papers instead of those from 

 text books; extensive bibliographies follow 

 each chapter, olfering the means for a compre- 

 hension of the extent of the work done and for 

 following up any particular subject;^ there is 

 a full index in which may be found the tax- 

 onomie position of all materials discussed; 

 scattered through the chapters are brief his- 

 torical or critical reviews of nomenclature; 

 there are frequent diagrammatic figures which 



1 As indicating the scope and character of these 

 refereneea it may be noted that at the end of 

 Chapter XI, "The Eeduction of the ChTomo- 

 somes, " a total of 170 individuals, of 11 nation- 

 alities, are quoted. The distribution of these 

 biologists is interesting, indicating, as it does in 

 a general way, the interest in cytology exhibited 

 in different countries. Of the 170 individuals 

 referred to, there are 54 Americans, 46 GermauB, 

 26 British, 13 French, 9 Japanese, 7 Scandina- 

 vians, 6 Belgians, 4 Hollanders, 2 Russians, 2 

 Italians, and 1 Pole. 



