144 



NATURE 



{Dec. 19, 1878 



buch der Botanik" has been lately translated by Pro- 

 fessors Bennett and Thiseltori Dyer, and which has been 

 published in the Clarendon Press Series. After the class- 

 book is mastered the manual is to be studied." 



The first class-book treats of the morphology and 

 physiology of plants. In it three chapters are devoted to 

 the morphology, and five chapters to the physiology. 

 Like the little text-book of Thomd, it presents to the 

 student's vie^y a cell of a fungal plant, as an instance of 

 the simplest conception of a vegetable cell ; but while such 

 a, structure is a cell, surely it is neither the most simple, 

 nor certainly is it the most perfect form of a cell to 

 be the first given to a beginner. The structure of the 

 cell-wall and its growth are well treated of, but we do 

 not like to find the word " absorption " used in the account 

 of the formation of wood vessels, bordered pits, &c. ; this 

 word is very likely to mislead the student, especially 

 when he finds it used in another chapter to denote 

 the imbibition of moisture. So far as we know, the 

 cellulose cell-wall is in no case decomposed molecule by 

 molecule, and these are not taken up as they are laid 

 down ; and yet would it not require that]]all this should be 

 done ere the term internal absorption could be correctly 

 applied ? 



The subjects of the formation of new cells, and of the 

 substances contained in protoplasm, are thoroughly well 

 done ; a few technical v/ords here and there occurring, and 

 not explained, will demand the attention of the teacher. 

 It would have been well had the chemical formulse 

 for starch, and some of the other members of the cellulose 

 group, be given, in addition to the formula for cellulose. 

 Such formulae would have enabled the student the better 

 to understand the change of one organic compound, such 

 as starch, into another, such as sugar. In passing we may 

 observe that Sach's " Text-Book " is very defective also in 

 this respect ; indeed, the word sugar is not to be found 

 in its index, and nowhere in the text is its composition 

 given. Chapter II. treats of the tissues. Perhaps a 

 few more technical words are here used than are abso- 

 lutely necessary, but no doubt a great deal of exactness 

 is attained by their use. The details are compressed into 

 the smallest compass, but are quite up to the very newest 

 facts ; and because each word in such a chapter stands 

 to express a good deal, we venture to take l^exception 

 to the employment of the word development in the 

 following sentence : — " Permanent tissue is formed by 

 the further development of those cells of the meristem 

 which have lost the power of dividing," and which have 

 assumed some permanent form. It is just in such cells 

 that no true development can take place. In Chapter III. 

 the external conformation of plants is briefly treated of* 

 In Chapter IV. we find The Nutrition of Plants. "As 

 the chemical elements out of which the plant constructs 

 its organic substance," the author enumerates " carbon, 

 hydrogen, oxygen, nitrogen, and sulphur ;" might he 

 not have added iron ? True, it may still be doubted 

 whether iron forms an integral constituent of the chemical 

 formula of chlorophyll, but without it the plant, as 

 a plant, cannot " construct its organic substance." 

 The processes of assimilation and metastasis are 

 very conveniently tabulated, and the student carefully 

 going over this chapter will, we should think, be able to 

 understand it withoAit any help from a teacher. It is a 



chapter which does the author great credit, and almost 

 comes up to the standard of the editors. Only one com- 

 ment we venture to make on it. Taking it for granted 

 that Nageli has somewhere said that the ultiinate solid 

 particles of plants are more or less crystalline, a concep- 

 tion beyond our powers, how then can the mode of their 

 growth be very different from that occurring in minerals, 

 crystals, &c. ? The Fifth Chapter is concerned with the 

 relation of the general conditions of the hfe of plants. 

 The Sixth treats of the growth of plants. The author 

 limits the term growth to an increase in bulk, accom- 

 panied by a deposit of some new constructive material. 

 He thus considerably limits the term, as we believe cor- 

 rectly defined by Herbert Spencer. The subject of the 

 tension found in growing parts is treated at a length out of 

 due proportion to the treatment of the other subjects in 

 the volume, and in such a class-book we think it would 

 have sufficed to have given the results of Sachs' experi- 

 ments on the periodicity of growth, and not to have 

 copied his tabular statements in such detail. The last 

 chapters are devoted to the subjects of the reproduction 

 of plants^and their classification. 



The second class-book, also by Prof. McNab, is a con- 

 tinuation of the first, but is devoted to the special morpho- 

 logy and outlines of a classification of plants. The 

 classification of the flowerless plants is based on that of 

 Sachs, though this is here and there altered. We think 

 the author acts rather prematurely in placing such famiUes 

 as those of the Chytridiaceae and Chlorochytridiaceae yet 

 as among the Oosporeae. The Lichens are regarded as 

 ascomycetous fungi parasitic on algae ; this we think 

 right. Cohn's very convenient names Bryophyta and 

 Pteridophyta are adopted for the groups of the mosses 

 and the Vascular Cryptogams ; and as an instance that 

 very recent facts in the life history of the Cryptogams has 

 not escaped the attention of the author, we perceive that 

 he mentions that the branches of the Horse-tails arise in 

 an axillary manner, and not as believed up to Janczewski's 

 researches, in an endogenous manner. So much space 

 is devoted to the Cryptogams that the treatment of the 

 flowering plants is greatly curtailed. These two little 

 volumes have been well and painstakingly compiled ; they 

 may be safely placed in the hands of a student who knows 

 some little of the subject about which they treat, and they 

 cannot fail to be very useful to every teacher of the 

 natural sciences in our upper schools. 



The two little volumes on "Zoology," by Prof. Macalister, 

 are of quite another type. They aim at presenting, in 

 as simple a form as possible, the leading characters of 

 vertebrate and invertebrate animals. In these, special 

 care has been taken to dispense with all unnecessary 

 technicalities, and when such, owing to the nature of the 

 case, arise, they are carefully explained. We would 

 have wished something more novel than most of the 

 woodcut illustrations, though we acknowledge that among 

 the invertebrates some of the illustrations are modern ; i 

 but we feel glad, to find each volume with a carefully 

 drawn up index, the loss of which will doubtless be felt 1 

 by many a -student of Prof. McNab' s two class-books;! 

 whiletheywill be found to afford trustworthy and accu- 

 ■rate information. This will be found given in a way 

 quite suited.to the .oanprehcnsion of our average minded 

 girls and boys. 



