January 9, 19U] 



SCIENCE 



73 



lowed this purpose to change materially the 

 presentation of " the large essentials of plant 

 life." " The effort is to include what has 

 proper place in the education of all young 

 people," and he distinctly excludes those spe- 

 cial matters which are best relegated to agri- 

 culture, horticulture, domestic science, for- 

 estry, etc. In other words, we have here what 

 the author believes all young people should 

 know about plants as a general foundation 

 for the subjects named, or even as a prepara- 

 tion for college botany. The present reviewer 

 is in hearty accord with this educational 

 theory, and he believes that in all well-con- 

 sidered schemes of education pure science 

 must precede applied science. 



The book is written in an easy, almost con- 

 versational style, and one wonders just how 

 it is likely to be used by the ordinary teacher. 

 It can scarcely be " recited " by the pupil, and 

 possibly this may be a point in its favor. 

 Perhaps this is why the author has added 

 questions after the chapters, usually a feature 

 of doubtful value, from the temptation it 

 offers to the illy-prepared teacher to hold the 

 book and ask the questions noted down before 

 him. 



Looking through the book, one is struck by 

 a freshness of statement, showing that the 

 author feels that he has a message for the 

 high-school pupils of the country, and this 

 continues with unabated enthusiasm from the 

 first paragraph of the introduction to the 

 closing paragraph of the book. It should do 

 much to place high-school botany in this 

 country upon a higher plane than it has ordi- 

 narily attained. 



A NICE LITTLE DIATOM BOOK 



One of the most attractive little books that 

 we have seen in many a day is one entitled 

 " BaciUariales " by H. v. Schonfeldt, and 

 published by Gustav Fischer, of Jena. It is 

 volume 10 of the series of booklets now in 

 course of publication entitled "Die Siisswas- 

 serflora Deutschlands, Osterreichs un der 

 Schweiz" and edited by Professor Doctor 

 Pascher, of Prag. There are to be sixteen of 

 these booklets, bound in limp cloth, each meas- 



uring about 11 X 19 cm. The book before us 

 gives ten pages to structure, cell-contents, 

 movements, reproduction, collecting, mount- 

 ing and the literature of the group. Then 

 follow 163 pages of systematic descriptions, 

 the general treatment following that by 

 Schiitt in Engler and Prantl's " Natiirlichen 

 Pflanzenfamilien." Fourteen pages are given 

 to the round diatoms (Centricse), including 

 eight genera and thirty-five species, while 

 about 150 pages are given to the long diatoms 

 (Pennatae) in which are included about 40 

 genera and 390 species. These figures empha- 

 size the statement often made that the round 

 diatoms are mostly marine, and the long dia- 

 toms mostly inhabitants of fresh waters. 

 Probably the truth is that in fresh waters we 

 find many more long diatoms, because there 

 are many more of them in the world at large, 

 but this does not wholly account for the great 

 disparity in numbers. 



There are 379 cuts in the text, which must 

 help the student greatly in his attempts to 

 understand the structure and especially the 

 markings of the cell-walls. A well-arranged 

 index of scientific names closes this handy 

 little book. One can not lay down this book 

 without the wish that some day we may have 

 something like it for this country. 



Charles E. Besset 



The University of Nebraska 



SPECIAL ARTICLES 



susceptibility GRADIENTS IN ANIMALS 



The writer has called attention in several 

 papers^ to the existence of axial gradients in 

 rate of metabolism in planarians and other 

 forms and their significance in relation to 

 polarity. During the past summer in the 

 course of other work at Woods Hole the op- 

 portunity presented itself to examine various 

 forms belonging to different groups and vari- 

 ous embryonic and larval stages for the exist- 

 ence of such gradients. 



The method used was that of determining 

 the relative susceptibility of different regions 



iJour. Exp. Zool., XII., 1912; Arch. f. Ent- 

 widkelungsmech., XXXV., 1913; XXXVII., 1913. 



