i893. SOME NEW BOOKS. 229 



become, and he does not accept Cayeux's view of the terrigenous 

 origin of Chalk as applicable to the Chalk as a whole, but considers 

 that "such evidence as is forthcoming from faunal considerations points 

 to an ocean which, if not abysmal, at least possessed depths far 

 exceeding those of many prominent marine areas." 



Space prevents any further notice of this interesting contribution 

 to Cretaceous history, the researches for which have been carried out 

 in the laboratory of the Royal College of Science ; and while con- 

 gratulating Professor Judd on the success of his choice of demon- 

 strators, we thank Dr. Hume for providing so much food for 

 reflection to the students of oceanic deposits, micro-zoology, and 

 geology. 



Lessons in Elementary Biology. By T. Jeftery Parker, D.Sc, F.R.S. With 88 

 illustrations. Second Edition. London : Alacmillan & Co., 1S93. Price los. 6d. 



Professor Parker's well-known text-book is designed for reading — 

 a complement to laboratory work with a text-book like the " Practical 

 Biology." It aims at teaching the ideas rather than the details of the 

 science of Biology — these ideas being studied in connection with con- 

 crete types of animals and plants. It is hardly necessary to do more 

 than welcome the second edition of a volume so familiar and so satis- 

 factory. It has been revised ; several new figures have been intro- 

 duced ; and the lessons dealing especially with cell-structure and 

 sexual cells (vi. and xxiv.) have been practically re-written. It is 

 hoped that the few notes now to be made will be taken, not as criti- 

 cisms directed against the book, but as footnotes which may be of 

 some use. 



On page 7 Professor Parker writes that " the theory is that proto- 

 plasm has a slightly acid reaction." This is very doubtful; it is 

 practically certain that the enchylema is slightly alkaline — and it is 

 doubtful if there is acid reaction in living protoplasm except in the 

 secretions in food vacuoles. 



On page 16 the author distinguishes between " true excreta " and 

 the solid excreta, or, "more correctly, faces, of Amoeba — the rejec- 

 tion of which latter is no more a process of excretion than the 

 spitting out of a cherry-stone." But certainly the " faeces " of the 

 higher animals are largely composed — not merely of undigested sub- 

 stances, but of matter actually excreted by the cells lining the 

 digestive tract. 



On page 21, where the author is discussing the effects of salt on 

 Amoeba, he conveys the impression, although he does not definitely 

 assert, that Amoeba is confined to fresh-water — whereas it is quite 

 common along the shore. 



In the section on Diatoms no mention is made of Biltschli's 

 account of the cause of their movement. (See Natural Science, 

 vol. i., p. 537.) 



SuBTERR.\NEAN I'iCARDY [La Picardie Souterraine. Album Compose de dix 

 Planches en Chromolilhographie reproduisant des Armes, Outils et autres 

 Utensiles en Silex trcuves dans les Alluvions Quaternaires de la Vallee de la 

 Somme (fipoques Chelleene et Mousterienne). Dessinees et Lithographiees en 

 couleur par M. Pilloy, officierd'Academie [etc.] ; et imprimeespar M. Bourbier, 

 Rue Saint-Jacques, 9, Saint-Quentin.] 4(0. Pp. 10, pis. x. Saint-yuenlin ; 

 Poette, 1892. 



Under this lengthy title we gladly chronicle a book of ten pages and 

 ten plates, relating chiefly to flint implements. The text is very 



