Botany. 587 



obtain the facts which he needs in regard to the forms and affini- 

 ties of the higher plants, but will lind in the treatise hardly any- 

 thing which may be called vegetable physiology, a subject 

 which examines the way in which medicinal as well as other 

 plants create their useful products. Some valuable hints in regard 

 to plant life are given here and there, but it is to be hoped that 

 in a fourth edition of the text-book, the chapter on the culti- 

 vation of medicinal plants may be so enlarged as to comprise the 

 underlying principles of plant-functions. The second part of the 

 book is given up to the examination of drugs, and is well propor- 

 tioned. More liberal use could well have been made of photo- 

 micrography, for the original illustrations as well as the copies 

 are most helpful. Professor Kraemer will perhaps hereafter 

 give greater definiteness to some of the statements regarding 

 very interesting points, which would be excellent subjects for 

 work by his advanced students ; such, for instance, as Hama- 

 melis. Excellent tables and keys make the work handy in the 

 best sense of the term, and render it useful' for food- and drug- 

 analysts as well as pharmacists. In important particulars, it 

 supplements some recent trustworthy treatises which are chiefly 

 devoted to food-products. For American students who are not 

 familiar with French or German, the present volume of Phar- 

 macognosy will prove invaluable. g. l. g. 



3. Die Gestalts- unci Lag ever cinder ung cler Pflanze?i- Chrom- 

 atophoren ; mit einer Beilage : Die Lichtbrechung der lebenden 

 Pflanzenzelle ; von Gustav Se^n. Pp. xv, 397, with 83 text- 

 figures and 9 plates. Leipzig, 1908 (Wilhelm Engelmann). — 

 In this volume the author has given the most complete account of 

 the changes in form and position of chlorophyll-grains and color- 

 granules which has yet been published. Its value is much 

 enhanced by the excellent table of contents and an exhaustive 

 iudex, but it is even more increased by what is, until recently, 

 lacking in most German treatises upon similar subjects, namely, 

 clear and comprehensive summaries or abstracts, at convenient 

 points throughout the work. When we remember that the 

 differentiated protoplasmic bodies which are collectively termed 

 Plastids, play such an important part in all plant activities, every- 

 thing which can add to the knowledge of the behavior of these 

 under external and internal influences must be heartily welcomed. 

 Dr. Senn has given us a well-proportioned treatise which embodies 

 the most essential features of the literature of the subject, and 

 has also added a supplement which considers a cognale matter 

 of great importance, namely, the refractive power of living* 

 vegetable cells. He gives to the clear cell-wall and its lining of 

 protoplasma the refractive index 1*47 to 1'52, while that of the 

 cell-sap therein contained is only a trifle higher than that of 

 water. From these figures it is not difficult to determine the 

 distribution of light and shade within the cells of living plants. 

 The bearing of this on the subject of ecology is very plain, g. l. g. 



