March 31, 1911] 



SCIENCE 



495 



placenta, menstruation, ovulation, age of 

 embryos and other related topics are given 

 proper attention, and put in the most modern 

 light. An excellent basis is laid by precise 

 description for further work in the histolog- 

 ical or pathological study of membranes and 

 uterine conditions, and a better idea is now 

 possible of the physiological environment of 

 early embryos, especially from the new young 

 human embryos described in detail. 



In his chapters (60 pages). Mall advocates 

 a new and improved method of measuring 

 embryos, which may also be applied to the 

 adult. His analysis of our knowledge of the 

 age of embryos, growth rate, etc., is original, 

 and results in new curves and tables of de- 

 velopment. He thus furnishes us a standard, 

 the result of a wide experience with all known 

 data. His chapter on pathological embryos is 

 novel and an advance in view point. It repre- 

 sents the essentials of his very extensive pub- 

 lications on this subject. The types of ab- 

 normalities, percentage of abortions, and the 

 association of the pathology of the membranes 

 with these are discussed. This leads up to an 

 analysis of the bearing which experimental 

 studies, mechanical and chemical, leading to 

 the production of definite monstrosities in 

 other forms, probably have on the origin of 

 abnormalities in human embryos. Medical 

 students and pathologists will turn to these 

 chapters freely, and general embryologists will 

 find here interesting significance in their 

 work. 



The second half of the first volume is de- 

 voted to the first chapters of the development 

 of special systems of organs, which will be 

 continued in the second volume. An examina- 

 tion makes it plain that these chapters were 

 not written for beginners, though the treat- 

 ment is direct and clear enough for any one. 

 Even this first volume is sufficient to show 

 that there is now ample material for satis- 

 factory courses in mammalian embryology of 

 advanced character, specially adapted to med- 

 ical stiidents. 



It is evident that the time has come for our 

 anatomical departments to insist that stu- 

 dents beginning anatomy should have already 



obtained, during their two years of pre-med- 

 ical college work now generally required, 

 sufficiently thorough courses in elementary 

 vertebrate embryology, to permit of properly 

 introducing them to the later stages, in man 

 and mammals, which have so much signifi- 

 cance for their work in human anatomy. 



The fifty pages by Pinkus, devoted to the 

 integument, proves to be a consideration of 

 many interesting aspects of the growth of the 

 skin structures often not insisted upon. Tor 

 in the treatment of pigmentation, glycogen, 

 fat, glands, hair and hair tracts, and of the 

 friction ridges and metamerism, we have 

 emphasized the value of more general studies 

 like those of Galton, Wilder, Sherrington, 

 Bolk and Harrison. The special circulation, 

 lymph supply, and nerve supply of the skin 

 are largely left for the writers who shall de- 

 scribe these systems. 



Bardeen's section (150 pages) on the skele- 

 ton and connective tissues may be character- 

 ized as encyclopaedic in the inclusion of so 

 great a mass of data. It is a storehouse of in- 

 formation, the variety of which has made the 

 task of collecting and arranging very difficult. 

 The author has exhibited much energy and 

 skill in handling the material, to which he has 

 contributed considerable of value. Mall's 

 views are accepted as the most reasonable for 

 the origin of the reticulum and fibrillse of this 

 tissue. Some of the most welcome sections 

 on the skeleton are those on joints, and on 

 variation and abnormalities in development. 

 The origin and changes of form of vertebra 

 are illustrated by Bardeen's models, a set of 

 which should be found in every anatomical 

 laboratory. The treatment of the develop- 

 ment of special regions of the skeleton, of 

 ossification centers, of the length and curva- 

 ture of the spine, is accompanied by valuable 

 figures and diagrams. The skeleton of the 

 limbs is taken up with similar fulness and 

 contains further contributions from the au- 

 thor, many figures new to text-books, and use- 

 ful tables. The skull is studied in forty pages 

 with a proper reference to comparative embry- 

 ology where also much has been done, and 

 such important complicated regions as the 



