September 29, 1916] 



SCIENCE 



467 



preceding chapters. The subject-matter is di- 

 vided as follows: Chapter VII., entodermal 

 canal; Chapter VIII., urogenital system; 

 Chapter IX., vascular system; Chapter X., 

 histogenesis, skin and muscles; Chapter XI., 

 central nervous system; Chapter XII., periph- 

 eral nervous system. Ductless glands are de- 

 scribed in Chapters VII., IX., XI. 



It will be seen from this statement of the 

 contents of the book that the subject-matter of 

 embryology is broadly represented. The treat- 

 ment of topics is in general proportioned to 

 their importance in the understanding of em- 

 bryology, as means for scientific training and 

 practical application. Descriptions are in the 

 main concise and clear. If we should classify 

 the book on the basis of material used in the 

 text and figures it would be a " mammalian 

 embryology " ; yet in order to meet the re- 

 quirements of the medical student of to-day, 

 examples of developmental processes from 

 lower forms are necessarily brought forward. 

 The directions for class-room dissection is a 

 most commendable addition to a laboratory 

 book on embryology since it will encourage the 

 adoption of this valuable method. While the 

 subject of histogenesis is extensively discussed 

 in text-books of histology it has not had a con- 

 spicuous place in the works on embryology 

 which are in common use among medical stu- 

 dents; Prentiss's book is an exception to this 

 case and the step taken in devoting a section 

 to the phenomena of differentiation of cells 

 and tissues will be appreciated. Another fea- 

 ture of this work for which the instructor will 

 be grateful is the large number of references 

 to original papers aptly dropped into the 

 text. Incidentally, a review of the names re- 

 ferred to brings out the fact that American 

 embryologists have taken no small part in con- 

 tributing to the science of development. The 

 book is amply illustrated by figures for the 

 most part well chosen. Many original draw- 

 ings are included, but the larger number com- 

 prises very properly figures taken from orig- 

 inal papers. The color work, as a whole, is un- 

 usually good. 



Mechanical errors are not as common as 

 might be expected in a first edition: a few 



may be indicated. On page 87, " convexity " 

 is printed evidently for " concavity " ; at the 

 bottom of page 234, " scroti " should be itali- 

 cized to conform with the type of " septum " ; 

 the adjective for "tear" is spelled in some 

 places "lachrymal," in others, "lacrymal." 

 The presswork is excellent throughout and the 

 choice of different type for the most part ef- 

 fective and in good taste. One exception 

 might be pointed out : in the selection of type, 

 the use of fine print in Chapter VI. in the 

 description of sections gives the impression of 

 secondary importance to this subject which is 

 unfortunate. Whereas the attention to sub- 

 jects is in general carefully proportioned, as 

 already stated, there are some instances of 

 inadequate treatment. The discussion of the 

 spleen is too brief and the same is true regard- 

 ing the origin of leucocytes. Almost nothing 

 is to be found in the book concerning the de- 

 velopment of the skeleton. Works on anatomy 

 usually include accounts of the ossification 

 but not of the early developmental processes. 

 Surely a text-book of embryology should pre- 

 sent the essential facts of the blastemal and 

 chondrogenous stages of the skeleton. A chap- 

 ter, or part of a chapter, might have been 

 given over to a consideration of growth and 

 postnatal development in order to emphasize 

 the importance of these subjects which are 

 represented by statements throughout the book 

 in connection with the description of organs. 

 Likewise the subject of histogenesis is not, 

 from a pedagogical standpoint, presented with 

 best effect coupled as it is in the same chapter 

 with subjects quite foreign to it. 



If we examine the author's method of treat- 

 ment of the whole subject of embryology in 

 presenting it to medical students, it is evident 

 that his book fits the peculiar needs of the 

 present time and to some degree points the 

 ways in which the science is growing. Through- 

 out, it inculcates the idea of the incomplete- 

 ness of our knowledge of embryology and the 

 need of working to gain fuller understanding 

 of developmental phenomena. The text is 

 descriptive of structure primarily, but also 

 largely of the processes of development. More 

 space could profitably have been given to phys- 



