500 SCIENCE PROGRESS 



A reprint of Laslett's Tables is added showing the results of tests on the 

 tensile, crushing, and breaking strengths of various timbers. The work 

 concludes with a chapter by S. Fitzgerald on the artificial seasoning of timber. 



There are a number of excellent photographic illustrations of which those 

 portraying the teak industry deserve especial mention. 



E. J. S. 



The Yeasts. By Alexandre Guilliermond, D.Sc, translated and revised 

 by F. W. Tanner, M.S., Ph.D. [Pp. xix + 424, with 163 Figures.] 

 (London : Chapman & Hall, Ltd., 1920. Price 335. net.) 



This book, originally appearing in French and now translated into English 

 and much enlarged both by the author and the translator, deals with the 

 yeasts, not only from the economic aspects, but from the more general stand- 

 point. The morphology, cytology, physiology and phylogeny of the yeasts 

 and yeast-like forms are fully described, and nearly half the book is given up 

 to a systematic survey of the group and to the treatment of the special physio- 

 logy and morphology of individual species. Prof. Guilliermond's researches 

 on the structure and relationship of these fungi are so well known that it 

 almost goes without saying that the poitions dealing with these special points 

 are treated in an interesting and critical manner. We are provided with an 

 account of the parasitic and symbiotic relationships of these organisms ; the 

 presence of vitamines ("accessory good substances'') in yeast and the practical 

 importance of this fact are enlarged on, and we are told that these substances 

 seem to be essential to the existence of the yeast plant. The full and broad 

 treatment of these subjects increases the general usefulness of the treatise. 



One cannot, however, feel such confidence in the translation. There are 

 places where, apparently, the very opposite is stated to what was intended ; 

 there are, also, innumerable occasions where the rendering is not as " free " 

 as could be desired. On page 38 we read, " To-day the nucleus is unique. . . . 

 Later on we shall take up nuclear division" on page 140, " At this moment 

 each of the cells divides its nucleus." " It never produces conidia, but, on 

 the contrary, forms a rather large number of ascs." The translator is 

 responsible also for the revision of the section on the physiology of these 

 organisms. Here, we find the term " hydro-carbon " continually used when 

 carbohydrate is meant ; and there is a tendency to diffuseness which at times 

 is confusing, e.g. the different and irreconcilable statements made as to the 

 possibility of yeast assimilating maltose. The book is well " got up " 

 and fully illustrated. 



E. M. C. 



Weeds of Farm Land. By Winifred E. Brenchley, D.Sc, F.L.S., Fellow 

 of University College, London ; Botanist, Rothamsted Experimental 

 Station. [Pp. x -j- 329, with illustrations.] (London : Longmans, 

 Green & Co., 1920. Price 12s. 6d. net.) 



The subject of this volume is one of great practical importance to the farmer, 

 for it deals with plants which are responsible, in a number of ways, for a 

 considerable reduction in the yield of his crops. Dr. Brenchley brings 

 together a large amount of information previously scattered through the 

 literature of agriculture and botany, and essays to make of it a collected 

 whole, laying no claim, however, to covering completely the entire ground. 

 First, the methods of distribution are discussed, the means by which the 

 weeds of farm land are brought into their position from adjoining fields or 

 from greater distances. In the former connection such practices as the 

 proper cleansing of farm implements are insisted on as necessary for the 

 restricting of a quite considerable source of transport ; in the latter it is 

 pointed out that very active agents of long-distance distribution are to be 



