LITERARY NOTICES. 



281 



an excellent sign of the times, as it be- 

 comes an index of activity in the field of 

 experimental work. But these little manuals 

 of practice are generally prepared with no 

 other view than to serve as convenient helps 

 in manipulation, and arc but rarely steps 

 in a broad, well-defined educational plan. 

 The little book before us is of a different 

 character, and has its place as part of a com- 

 prehensive system of biological study. 



Professor Martin, who has charge of 

 biology in Johns ITopkins University, has 

 organized his department of teaching on a 

 rational basis, and this book is the first in- 

 stallment of a series of small hand-books 

 which has had its origin in his experience 

 and necessities as a teacher. His theory of 

 the method of study, which is hardly new, 

 but has not been before reduced to a work- 

 ing system, is that students should first ac- 

 quire some general idea of the elements and 

 relations of their subject before concentrat- 

 ing study upon special divisions of it. In 

 accordance with this idea, he some years 

 ago, in connection with Professor Huxley, 

 issued a volume called " Practical Biology," 

 which was designed to introduce students to 

 this science by observations of the struct- 

 ure and life-history of a number of typical 

 plants and animals. It assumed that there 

 is properly a science of living beings, as 

 such, quite apart from any division of them 

 into animals and plants. The course of 

 study prescribed was experimental and thor- 

 ough, and designed to lay a firm foundation 

 for the further pursuit of the subject. Be- 

 ing thus grounded in general biology, the 

 student is prepared to take up botany, or 

 animal anatomy and physiology, and pro- 

 ceed with them to the greatest advantage. 

 The present hand-book comes in at this point 

 when it is proposed to enter upon the sci- 

 entific investigation of vertebrates, and it 

 shows him "how to dissect a chelonian." 

 The Chelonia are reptiles of the tortoise 

 kind, and among these Professor Martin 

 selects the Red-bellied Slider Terrapin for 

 dissection, and adapts his book to the details 

 of its structure. But, if students can not 

 find this species, Professor Martin says that 

 it is quite as well, and even in some respects 

 better, to obtain species slightly different 

 from the one described; the attention of 

 students being kept more alert when they 



find they can not altogether rely on the de- 

 scription in the book, but have to look at 

 everything carefully for themselves. 



The present monograph will shortly be 

 followed by two others, containing direc- 

 tions for the dissection of a pigeon and a 

 rat, both of which are nearly ready for pub- 

 lication. The series will ultimately include 

 a bony and a cartilaginous fish, a lizard, 

 and one of the large-tailed amphibia, and 

 when completed the series will form a 

 Hand-book of Vertebrate Dissection. 



Algebra for Schools and Colleges. By 

 Simon Newcomb, Professor of Mathe- 

 matics, U. S. Navv. New York : Henrv 

 Holt & Co. 1881. Pp. 454. Price, 

 $1.90. 



A characteristic of this book is that, 

 for the convenience of teachers, it is divided 

 into two parts : the first adapted to well- 

 prepared beginners, and comprising about 

 what is commonly required for admission to 

 college ; and the second designed for the 

 more advanced general student. 



In the preparation of his work, Pro- 

 fessor Newcomb recognizes two important 

 principles in education which are much 

 overlooked, and are novelties in their ap- 

 plication to algebra. The first is that, in 

 the acquisition of knowledge, an idea can 

 not be very fully grasped by the youthful 

 mind unless it is presented under a concrete 

 form. This requires that, whenever possi- 

 ble, an abstract idea should be embodied in 

 some visible representation, and all general 

 theorems presented in a variety of special 

 forms. In accordance with this principle, 

 numerical examples of nearly all algebraic 

 operations and theorems have been given. 

 Algebraic operations with pure numbers are 

 made to precede the use of symbols, and 

 the latter are introduced only after the pu- 

 pil has had a certain amount of familiarity 

 with the distinction between algebraic and 

 numerical operations. The second principle 

 is the importance of time in mental proc- 

 esses. All mathematical conceptions re- 

 quire time to become ingrafted upon the 

 mind, and the greater their abstruscness the 

 more time is needed. The author is of 

 the opinion that the backward state of math- 

 ematical instruction in this country, as com- 

 pared with Europe, is due to a neglect of 



