September 24, 1903] 



NATURE 



495 



reference to the illustration. It is true this is well 

 lettered, but no explanation is furnished as to what 

 each letter denotes. Many of the figures prepared 

 specially for the book from photographs are of little 

 use. 



In a word, the book would have been more accept- 

 able if the author had confined his attention to the 

 matters really included in the title, and had supplied 

 better illustrations. 



EXPERIMENTAL SCIENCE FOR BEGINNERS. 



Practical Chemistry. By Walter Harris, M.A., Ph.D. 

 Vol. i. Measurement. Vol. ii. Exercises and Pro- 

 blems. Vol. iii. Qualitative and Quantitative 

 Analysis. Pp. x + 91; ix+172; vii+146. (London: 

 Whittaker and Co., 1903.) 



THERE are probably few teachers, who, with half- 

 a-dozen pupils and plenty of time to devote to 

 them, would not prefer the oral to the book process of 

 imparting the elements of experimental science. Yet 

 when the number in a class is large, and laboratory 

 work is limited to one or two hours a week — the usual 

 order of things in schools — the demonstrator must be 

 relieved by the aid of some form of printed instruc- 

 tions. 



In compiling a book of this kind, the chief difficulty 

 which presents itself is to know how much to tell 

 about the processes, and how much to leave to the 

 pupil's intelligence and initiative. 



Given the budding philosopher and plenty of time, 

 very little book direction is necessary, and he may 

 safely be left to worry out details for himself. The 

 everyday youth is not a philosopher, and if, in addi- 

 tion, he has only one hour a week in the laboratory, 

 he must be helped to his results in a very substantial 

 manner, to enable him not only to absorb a variety 

 of facts in the time at his disposal, but (and this is 

 equally important) to avoid the discouraging conse- 

 quences of repeated experimental failures. These 

 points have been recognised in the three little volumes 

 which together make up Dr. Harris's " Practical 

 Chemistry." Vol. i. deals really with elementary 

 physics, and contains exercises in measurement of 

 length and volume, mass and density. Vol. ii. con- 

 tains easy qualitative and quantitative experiments in 

 chemistry. The third volume contains the elements 

 of qualitative and quantitative analysis, in reference 

 to which the author laconically remarks that " for 

 those who do not require this section for examination 

 purposes, it should be omitted." The experiments in 

 the first two volumes are numerous, simple, and sug- 

 gestive, and well adapted for a school laboratory, and 

 there are many things which will be found of value 

 to the teacher as well as to the student. 



One feels compelled to differ from the author on the 

 subject of illustrations. The author says : " The omis- 

 sion of all illustrations of apparatus is a new de- 

 parture." Is it a good one? We must remember 

 that the beginner does not recognise by name even 

 " the permanent apparatus commonly seen in labora- 

 tories," and although it is very desirable that "the 

 student should be encouraged to devise his own ap- 

 NO. 1769, VOL. 68] 



paratus," it is a process which is certain to result in 

 failure and loss of time. Those who have attempted 

 with all the knowledge of laboratory resources to 

 reduce an apparatus to a simple form, will recognise 

 how troublesome the process is. Moreover, the authc«: 

 gives no directions for working glass; which, one 

 would suppose, would be the first step in fitting up 

 glass apparatus. 



May one further suggestion be offered? Experi- 

 ment I, in section ii., on homogeneous and hetero- 

 geneous substances, is not a single experiment at all, 

 but a very condensed account of the separation of 

 solids and liquids, in which filtration, sublimation, 

 levigation, and fractional distillation are discussed in 

 turn. This and some other chapters would be im- 

 proved by dividing them up and by giving, in addi- 

 tion to general principles, a description of specific 

 instances, from which the teacher might make his 

 own selection. 



There is no doubt that these volumes will form a 

 useful addition to the modern literature on science 

 teaching. J. B. C. 



OUR BOOK SHELF. 



U titer suchun gen iiber Amylase und Amyloseartige 

 Korper. By O. Butschli. (Heidelberg: Carl 

 Winter, 1903.) 



This pamphlet of about 100 pages is a reprint from 

 the Proceedings of the Heidelberg Association for 

 Natural History and Medicine (vol. vii. part iii.), 

 which is one of the best known of the German scien- 

 tific societies. It illustrates a tendency, not infre- 

 quently seen in Germany, to utilise the pages of a 

 journal for the issue of what is practically a book. 

 The author, Prof. Butschli, is well known to students 

 of biology for his work on protoplasm, and distant as 

 the subject of starch may at first appear from zoo- 

 logical studies, the present research is a direct outcome 

 of the former. The microscopic investigation of 

 various colloids occurring in nature which led Butschli 

 to his well-known hypothesis of the foam-like structure 

 of protoplasm caused him later to direct his attention 

 to the formation of starch grains, cellulose membranes 

 and the like in the vegetable world. Some years ago 

 he published his view .that starch grains are of the 

 nature of sphaero-crystals. From this he passed on 

 to attempt to prepare starch grains artificially from 

 starch solutions, and he was rewarded by the dis- 

 covery that, under certain conditions, especially on 

 evaporating a solution containing also 5 per cent, of 

 gelatin, particles differing but slightly from natural 

 starch grains are deposited. These results were 

 criticised by Arthur Meyer, who expressed the opinion 

 that these particles consisted not of starch, but of 

 amylodextrin. The present pamphlet is a reply to 

 these criticisms, and on the ground of various chemical 

 reactions the conclusion is finally reached that Meyer 

 was wrong, and the author right in his original con- 

 tention. 



This is the gist of the monograph, and its length 

 is due to the fact that it became necessary for the 

 author to make a chemical investigation of various 

 starches, dextrins, and allied carbohydrates in order 

 to justify his main conclusions. 



From the purely chemical standpoint very little real 

 progress is contributed to our knowledge of the carbo- 

 hydrates. The sugars, thanks to Fischer and others, 

 we now know something about, but concerning the 



