April i i , 1^95] 



NA TURE 



555 



whole organism is only subsidiary when the relation of 

 leaves to the rest of the plant is considered. 



The chapters on the general processes of horticulture ; 

 the correlation of stems and roots, and their separate 

 treatment ; the principles of manuring ; the theories of 

 the proper supply of water to the plant, the aeration of 

 its roots, &c., will be read with much attention, and will 

 be found very useful in actual practice. The deposition 

 of nutritive material in various parts of the plant, and 

 the ways in which this can be influenced by different 

 modes of treatment of the shoot at different ages, deserve 

 careful study. The relation of such questions to the 

 operations of pruning, grafting, &c., is discussed at some 

 length, and the development of vegetative or fruiting 

 branches respectively, is shown to be capable of great 

 modification in the hands of the skilled horticulturist. 



The book, however, though a valuable one for prac- 

 tical gardeners, leaves something to be desired as a 

 contribution to the literature of vegetable physiology. 

 Indeed some of the fundamental facts of the metabolism 

 of the cell are, if not inaccurately, at any rate not clearly 

 stated. The absorption of water is certainly one of the 

 most important processes which it carries out. As de- 

 scribed on p. 127, the early changes in the young cell 

 connected with this process are stated as follows : — 



" Very soon there arise within the protoplasmic mass 

 which fills up the cells, very small quantities of liquid 

 substance (cell sap) which collect together to form small 

 vesicles (vacuoles), and these give to the protoplasm a 

 foam-like structure. Now, as the protoplasm becomes 

 used up during the elongation of the cells, the vacuoles 

 increase in number, run together, and force the remainder 

 of the protoplasm outwards towards the cell wall." 



Put in this way, the student would get the idea that the 

 elongation of the cells takes place apart from the entry 

 of water, and that the formation of the vacuole, that is, 

 the increase of the cell-sap, is rather the result than the 

 cause of the extension of the cell. No statement is made 

 as to the cause of the entry of the water, the osmotic 

 activity of the cell-contents, which really underlies all 

 cell-growth. 



Another strange statement is that the main cause of 

 the growth in length of a young stem is the longitudinal 

 tension in- the pith, which "drags the young ring of wood 

 with it, as long as the latter is still soft and thin-walled." 

 This will be a new view to most physiologists. 



Dealing with the absorption of nitrogen by certain 

 leguminous plants, and the recently established fact that 

 the atmosphere is a source of supply of this constituent^ 

 the author commits himself to the view that this 

 absorption is carried out by means of their leaves. 



In section 23, which treats of the substances formed by 

 the leaves, we find several statements to which exception 

 must be taken. The classification of the vegetable 

 proteids is inaccurate, the latter being said to consist of 

 albumins, caseins, and fibrins. Albumins are extremely 

 rare in plants, and fibrin resembling animal fibrin is un- 

 known. Globulins, which are numerous and varied, and 

 albumoses, which have comparatively recently been in- 

 vestigated, are not even mentioned. The formation of 

 starch grains in the leaves is thus described — 



" When the light shines on the leaf its transpiration is 

 exactly increased, and its cells lose some of their water ; 



NO. 1328, VOL. 51] 



then we may imagine the starchy substance to be forced 

 out of the thickened (concentrated) cell-sap, and the 

 latter will become more liquid.' 



The nutrition of the cell is summed up in the remark- 

 able sentence : 



" The nutrition consists in this, that the raw mateiials 

 which enter the cell are attracted, now by one, now by 

 another of the constituents of the cell, and adopt its 

 specific movements, and are thus transformed with the 

 same substance (assimilated)." 



These drawbacks to an otherwise valuable work make 

 one regret that Prof. Weiss has confined himself to trans- 

 lating Dr. Sorauer's text. Had he rather edited than 

 translated it, no doubt we should have found the English 

 edition free from these defects. 



MINES AND MINERALS. 

 Traiie ties Cites Mincraux et Metallifcrcs. Cotirs de 

 G^ologie appUqu^e de VEcole SupMeure des Mines. 

 By E. Fuchs and L. de Launay. (Paris: Baudry, 



,18930 

 Etude industrielle des Gites M^tallifires. By George 

 Moreau. (Paris: Baudry, 1894.) 



IN these days, when memoirs and papers follow in 

 rapid succession, the geologist and the miner are 

 justly grateful to any careful compiler who will aid them 

 to keep pace with the ever-widening flood of technical 

 literature. The debt of gratitude is increased when the 

 task is undertaken by a writer like Prof, de Launay, who 

 brings together into one colossal work the results of the 

 labours of his master, the late Prof. Fuchs, and of his 

 own personal researches. 



The book is a treatise upon applied geology, which 

 Fuchs defined as the application of geological knowledge 

 to seeking and working mineral deposits. Very rightly 

 Fuchs took a wider basis for his course of lectures at the 

 Paris School of Mines than mere ore deposits. He 

 recognised the fact that the mining engineer of to-day 

 must be a man of wide attainments, capable of giving an 

 opinion upon all sorts of mineral workings, reporting 

 upon gold mines in one journey, upon gem-diggings in 

 the next, and a little later being asked to determine the 

 value of deposits of phosphate of lime or other earthy 

 minerals. For work of this description Prof. Fuchs' 

 lectures formed an admirable kind of training, which has 

 too often been neglected in the past ; in fact, until this 

 treatise appeared, many geologists may have failed to 

 realise the vast importance of the subject. 



While admitting that various systems of classification 

 may be adopted. Prof, de Launay says that he felt bound 

 to arrange his minerals according to the metalloid or the 

 metal, and he chooses the so-called chemical order. In 

 a huge book of this description, alphabetical order would 

 have been more convenient, and would have prevented 

 some of the anomalies which cannot help striking the 

 reader. The chloride, carbonate, and sulphate of sodium 

 appear under the head of that metal, whilst the borate 

 and nitrate are classed respectively under boron and 

 nitrogen ; again, chalk and gypsum are brought under 

 calcium, whilst apatite is placed under phosphorus, no 

 doubt for the reason that the non-metallic element is the 



