NOYEMBEE 27, 1914] 



SCIENCE 



787 



tigations relating to physical constants and 

 properties of proteins. This line of study, aa 

 tlie author remarks, certainly deserves consid- 

 eration on the part of chemists and biologists, 

 although it is not yet satisfactorily developed. 

 The book is divided into four parts : (1) chem- 

 ical statics in protein systems (dealing with 

 preparations of pure proteins and hypotheses 

 concerning protein compounds) ; (2) electro- 

 chemistry of proteins (conductivity, etc) ; (3) 

 physical properties of protein systems; (4) 

 chemical dynamics in protein systems (hydrol- 

 ysis of proteins, action of enzymes). Nat- 

 urally the author's own investigations are dis- 

 cussed at length. In these he tries to apply 

 those quantitative laws which, as a rule, are 

 classified specifically as physicochemical : the 

 gas laws, van't Hoff's theory of dilute solutions 

 and all those other laws which can be derived 

 from them on the basis of thermodynamics. 

 The numerical data of the measurements fit 

 the calculations well in most cases ; the conclu- 

 sion of the author, however, that protein solu- 

 tions do not contain discrete particles does not 

 seem perfectly justified, since investigations by 

 Einstein and by Perrin have shown that even 

 emulsions allow the application of the gas law 

 in a certain form. ISTevertheless the book wUl 

 certainly prove extremely useful as a manual 

 for all those who are interested in the further 

 development of this important branch of 

 science. 



R Beutnek 



Die Yorzeitlichen Bdugetiere. By O. Abel. 

 Jena, Gustavo Fischer, 1914. Pp. v + 309, 

 with 250 figures and 2 tables in the text. 

 In the introduction the author emphasizes 

 the dominance during the Mesozoic of the 

 great reptiles— dinosaurs on land, mosasaurs 

 in the sea, pterosaurs in the air — ^which, 

 though mammals, had existed from the Upper 

 Trias to the limit of the Cretaceous, put an 

 effective check upon their evolutionary ad- 

 vancement. The principal abiding place of 

 the mammals has always been the continents, 

 yet by Middle Eocene time one finds the sea 

 mammals, such as the whales and Sirenia, al- 

 ready evolved, and although the aerial realm 



has never been a domain of the mammals, the 

 bats have for a long time competed with the 

 birds, the heirs of the pterosaurs. 



According to Steinmann, the different rep- 

 tilian stems were not extinguished at the end 

 of the Cretaceous period, but the great dino- 

 saurs are said to have still existed in the great 

 land mammals of the Tertiary, the ichthyo- 

 saurs in the dolphins, the mosasaurs in the 

 baleen whales, the plesiosaurs in the sperm 

 whales, the pterodactyls in the bats. This 

 view Abel refutes upon anatomical and other 

 grounds, and derives the mammals from a 

 much more primitive reptilian stock. The au- 

 thor discusses the remarkable preservation of 

 fossil mammals, as seen in the asphalt beds 

 of the Eancho La Brea in California, frozen 

 cadavers in the tundras of Siberia and those 

 preserved in the oil-steeped soil of Galicia 

 and the dry caverns of Patagonia, as well as 

 in the ordinary mineralization of the bones. 

 The principal localities which have produced 

 mammalian remains are recorded; first those 

 of the Mesozoic, then the European localities 

 in their geologic sequence, followed by those 

 of Asia, Africa, North America, South Amer- 

 ica and Australia in the order named. A very 

 carefully wrought out chronological table is 

 given, correlating the faunas of the five con- 

 tinental regions, the North American column 

 presenting the six successive faunal phases as 

 originally proposed by Osborn. 



The oldest mammalian remains are dis- 

 cussed, no Permian ones being known, but the 

 Upper Trias producing forms which seem to 

 point toi an origin at the latest by Permian 

 time. The position of the ancient mammals 

 in the " system " of living mammals is next 

 dealt with historically. Abel recognizes the 

 difficulty of erecting a system of classification 

 which shall also give the phylogenetie stages 

 in the history of any stock, and states that it 

 almost seems as if it were impossible, on the 

 basis of our present taxonomy, to form a sat- 

 isfactory compromise between that and 

 phylogeny. His own classification, though 

 in many cases it does not give full recognition 

 to phylogenetie facts, seeks, where possible, to 

 lay emphasis on the historic and genetic 



