October 31, 



1895] 



NA TURE 



641 



The cases where amylo-dextrine occurs, and the 

 relations of all these substances to other carbohydrates, 

 their behaviour in water of various temperatures, the 

 action of diastase, and so forth, are discussed at great 

 length, and we are glad to see that the author has paid 

 attention to, and, it may be added, been considerably 

 influenced by, the valuable work of Brown, Heron, Morris 

 and Salomon, and there are points of discussion of 

 interest to all these workers. 



Of course a view like Meyer's must depend for its validity 

 essentially on what experimental results can be got in 

 the way of obtaining sphere-cr)'stals of carbohydrates 

 like amylose under known conditions ; if the author's 

 statements regarding the crystallisation into spherites of 

 inulin and amylodextrin and other bodies in a \iscous 

 matrix can be extended to the case in point — where the 

 protoplasm of the amyloplast acts as the viscous matrix — 

 he has certainly made out a strong case, for all the 

 ordinarj' physical properties of porosity, behaviour to 

 polarised light, swelling, and the stratification, striation, 

 and other structural peculiarities of the starch-grain are 

 as easily explained if the unit of structure is a trichite 

 as where it is assumed to be a micella. 



Since it is as yet impossible to artificially crystallise 

 the amylose composing the chief part of a normal grain, 

 into the spherical shape, however, the war of discussion 

 will no doubt rage around this point ; in the meantime, 

 Meyer has unquestionably marshalled his facts in hea\'>' 

 order and made out an ingenious case, the full signifi- 

 cance of which can only be grasped by ploughing one's 

 way through his heavy, but, in the main, logical German. 



The phenomenon of swelling has always been a crux 

 in hypotheses regarding the structure of organised bodies. 

 Meyer explains it as due to the trichites o{ ^-Amylose — 

 the principal constituent of the normal starch-grain — 

 absorbing water, and themselves swelling. In other 

 words, the water dissolves in the crystals. 



It should be noted, however, that Meyer distinguishes 

 sharply and emphatically between Porcnqicelliing, where 

 water is merely imbibed between the crystals, and /.^.f//«_^j-- 

 gitc/lung, where the water is taken up by the crystals ; 

 and he here emphasises what may be a useful distinction 

 in questions of imbibition. It is, of course, Losiings- 

 gitc/liing which initiates the disorganisation of the grain. 



In the discussion of the question as to the growth of 

 the starch-grain, the author points out that the latter may 

 grow in chromoplasts, as well as chloro- and leuco- 

 plasts, and that the grain never impinges on the cyto- 

 plasm — it is always completely surrounded by a layer, 

 however thin, of its plastid so long as the cell lives ; he 

 makes this seem probable, but it is impossible to prove 

 it in some instances. In any case, the reader will find 

 some pretty staining methods brought to bear on the 

 point. 



Of course the grain grows by apposition, and the 

 thickness of the layer deposited depends on that of the 

 protoplasm in contact at the place. On the whole, 

 indeed, the laws of growth and stratification are those 

 laid down by .Schimper and .Strassburger, though Meyer 

 adds a good many facts as to the initiation and growth 

 of both simple and compound grains, and has devised a 

 new nomenclature and classification of the various kinds 

 of starch-grains which, complete and exhausti\e though 

 NO. 1357, VOL. 52] 



it appears, we confess does not seem to meet the require- 

 ments of clearness and simplicity so fully as could be 

 desired. 



One of the most ingenious chapters in the book is 

 that on the solution of the grains in the cell, and the 

 significance of fissures and pores for the attack of the 

 diastatic or other solvent. 



Space is not available for detailed remarks on the 

 authors methods of examining the changes which the 

 starch-grains undergo in the various organs of Aitoxa, 

 Hordeum, Dieffenbachia, Pellionta, Hyacinlhus, Oxalis, 

 &c., at different times of the year and under different 

 conditions ; nor to give his views on the constitution of 

 protoplasm — which we \enture to think too much of the 

 nature of a hastily-written note, moreover not necessarj' 

 to the subject, and far from convincing in the six pages 

 (with critical sentences on everybody from \aegeli and 

 Wiesner to Biitschli interspersed) devoted to it. Put 

 briefly, Meyer regards protoplasm as a peculiar emulsion, 

 and therein agrees essentially with Berthold ; whereas 

 the elements of cell-w-alls and starch-grains are as truly 

 crystallised out as is calcium oxalate. 



The experiments showing that the position of the 

 layers of the starch-grains can be altered by changing 

 the position of the organ in which they are growing, and 

 that the alternation of day and night is e.xpressed in the 

 thickness and density of the layers — that the layers are 

 " diurnal layers " — in effect (pp. 268-271) are well worth 

 attention, however, as indeed are very many others of 

 the difficult experimental points brought out towards the 

 end of the book. 



That the questions centering around the starch-grain 

 have not reached finality, is obvious, but that Meyer has 

 contributed a valuable attempt to set some of them at 

 rest, must be admitted by all who read his monograph. 

 It bristles with debatable points, and there are some 

 annoying faults — e.g. the frequent references to figures 

 and titles in the text without sufficient clues, and to 

 chapters ahead of the reader ; but that does not weaken 

 the fact that his results stimulate the reader to some 

 close thinking, and his critical compilation of the historj' 

 and literature of the subject alone makes the book 

 necessary to all working botanists. 



H. M.\KSH.\LI, W.\RD. 



APPLIED METEOROLOGY. 

 Weather and Disease. A Cui~'e History of their Varia- 

 tions in Recent Years. By .A.lex. B. MacDowall, M..A., 

 F.R.Met.S. (London: The Graphotone Co., 1895.) 



THE systematic study of climatic conditions in 

 connection with the fluctuation in the public health, 

 is one which has only recently been undertaken, but 

 which already promises results of a most interesting and 

 important character. .Apart from the inherent interest 

 of the subject, which must indeed be apparent ; the study 

 offers, like observations in phenology, the prospect of 

 great practical value. The work of weather forecasting 

 is at present so wanting in accuracy, and there is so 

 little promise of progress in this direction, that practical 

 meteorologists might be tempted to despair, and the 

 general public be led to imagine that the vast stores of 

 records which ha\e been accumulated were destined to 



