244 NOTICES OF BOOKS. 



medical schools of London — are responsible to some extent for this 

 unsatisfactory state of things ; there has been a dearth of real 

 students of the subject, and a large demand for books sufficient to 

 enable students of medicine to pass their examinations. The appear- 

 ance of this English translation of Sach's " Lehrbuch " must be hailed 

 as a sign of better times, and an indication that a class of students of 

 a more earnest sort is springing up. For such only is it intended, or, 

 in its present extended form, suitable. 



The '' Lehrbuch derBotanik" of Prof. Sachs was first published, in 

 two parts, in 1868, and rapidly passed through two editions, the preface 

 to the third being dated Xovember, 1872. It is this edition of which we 

 now have a translation into English, and of which an excellent French 

 edition, with valuable notes by M. Van Tieghcm, was published last year. 

 Since then another, the fourth, edition of the original has appeared, 

 and as it has been passing through the press concurrently with this 

 English translation, it has been possible to incorporate some of the 

 new matter as footnotes in the latter. 



The treatise consists of three parts ; the first deals with General 

 Morphology, the second and most extensive with Special Morpho- 

 logy, and the third with Physiology. In the first part the lead- 

 ing chapter is devoted to consideration of the form and structure 

 of the cells and their contents, the next to morphology of the tissues, 

 and the third to the origin, modes of growth, forms and positions of 

 the different members of the plant. In the part dealing with Special 

 Morphology the subject is treated under the groups of 1 Tliallophytes 

 (Alga3, Fungi), 2 CharacecB, 3 Muscinem (Hepatic;©, Mosses), 4 Vas- 

 cular Cryptogams (Ferns, Equisetace^, Ophioglossaceae, Rhizo- 

 carpece, Lycopodiace^), 5 Flianerogams (Gymnosperms, . Monocotyle- 

 dons, Dicotyledons). Under each of these divisions is a very fall and 

 minutely accurate account of its structure and reproductive processes, 

 with an outline of classification; nothing comparable with this 

 review of the vegetable world is to be found elsewhere in print. 

 Both these parts are copiously illustrated with woodcuts in the text 

 of the highest merit, and either original or taken from memoirs of 

 important researches. Under Physiology, in the third part, come in 

 succession accounts of the molecular forces and chemical processes in 

 the plant, the influence of the external conditions of temperature, light, 

 electricity, and gravitation on vegetation, the mechanical laws of growth, 

 the phenomena of movement and of sexual reproduction, and, lastly, a 

 chapter on the origin of species and the theory of descent. 



It will thus be seen that the whole subject of the structure and 

 life history of plants is covered. The classification of the vegetable 

 kingdom is but slightly touched upon, except as subordinate to the 

 structural facts. The author's new views (as found in the fourth German 

 edition) of ^ the classification of the Thallophytes is given as an appen- 

 dix ; in this the distinction between Alga) and Fungi is abandoned as 

 one of primary importance.*' As indicated above. Lichens are not dis- 

 tinguished as a class; the views of Schwendener are fully adopted in 

 the text, and Lichens considered to be true Fungi of the section Ascomy- 

 cetes, but only known as parasites on various filamentous and unicellular 



* As also in Cohn's proposed classification (Journ. Bot., 1872, p. 114.) 



