386 



NATURE 



[August 27, 1903 



investigate this question further. In an experiment 

 given later, done with a lower sugar concentration 

 than in the above, the yield of alcohol approaches the 

 calculated amount. 



Glycerol is probably not found in the cell-free 

 fermentation, and is considered a product of cell- 

 metabolism, a similar view to that held by Pasteur 

 about ethyl alcohol. May not the production of 

 glycerol and other higher alcohols be equally due to 

 the action of soluble ferments not yet discovered? 



The experiments on regeneration of yeast, which 

 conclude part i., serve to show how much work re- 

 mains to be done in this direction. The whole account 

 of the general research is given in a lucid and interest- 

 ing manner, and deals with many lesser matters 

 arising out of the main thesis, each point being illus- 

 trated by tables of the actual experiments performed, 

 and the results of the experiments are fully discussed. 

 The author establishes himself especially firmly where 

 other investigators have questioned some of his work. 



Part ii., by Profs. Hahn and Geret, gives an account 

 of the discovery of endotryptase by the former author, 

 the description of the experimental work being 

 followed by a good summary. 



Part iii. is by Prof. Hahn alone, and describes the 

 reducing properties of yeast-juice as shown by experi- 

 ments performed by himself and Dr. Cathcart. Some 

 reasons are given for the author's thinking that the 

 reducing power is due to the same ferment, zymase, 

 which induces alcoholic fermentation. 



Part iv., by Profs. Hans Buchner and Rudolph 

 Rapp, is on the relation of oxygen-supply to the fer- 

 menting power of living yeast-cells. 



The contradictory results of previous workers are 

 first reviewed, Pasteur's theories being considered and 

 Chudiakow's work repeated and examined critically 

 in detail. The latter had found that air had no effect 

 on the fermenting power, but that it killed yeast-cells 

 more rapidly than hydrogen, when each was drawn 

 through a sugar solution containing a small quantity 

 of the yeast. The authors find that his results were 

 partly due to defects in his aspiration methods, more 

 air than hydrogen being drawn through in a given 

 time, with consequent injury from shaking. They 

 state also that he used a yeast of too little vitality for 

 general conclusions. They find that neither air nor 

 hydrogen, as such, affects the fermenting power, and 

 that the mechanical shaking of the fluid is detrimental 

 if it exceed a certain limit. The effects of air and 

 hydrogen differ only in that the former induces a slight 

 multiplication of the yeast cells, and thus leads to a 

 rather larger production of CO^. 



The authors then pass on to investigate the effect of 

 air on cultures of yeast grown on beer-wort-gelatin 

 with 10 per cent, of glucose. Here, with a free supply 

 of air, they find one part of sugar oxidised to every 

 five parts fermented. The yeast multiplies more 

 rapidly under such conditions than when very little 

 air is supplied, but in the latter case a given weight 

 of yeast ferments more sugar. 



The whole volume is full of interest and instruction, 

 and cannot fail to give the greatest pleasure to a 

 student of alcoholic fermentation. 



Arthur Croft Hill. 

 NO. 1765, VOL. 68] 



^iV INDIAN FLORA. 

 The Flora of the Presidency of Bombay. Vol. i. 

 Ranunculaceae to Rubiaceae. By Theodore Cooke, 

 CLE., M.A., M.A.I. , LL.D., F.G.S., 

 M.Inst.C.E.I. Pp. 645. (London: Taylor and 

 Francis, 1901-3.) Price 27s. 



THE labours of botanists and of a small band of 

 foresters, in India. and at Kew, have supplied 

 us with rich stores of information as to the Indo- 

 Malayan flora. These rendered possible the issue of 

 Sir Joseph Hooker's monumental " Flora of British 

 India." 



But British India and Malaya, including as they 

 do countries far apart, with climates ranging in 

 temperature from low alpine to high torrid extremes, 

 in humidity from the perpetual aridity of the desert 

 to the permanent moistness of the equatorial tropics, 

 exhibit subfloras and kinds of vegetation of correspond- 

 ing variety. In order to map out these separate floras 

 of British India, including Burma, the Government of 

 India has decided to issue a series of " regional 

 floras." Such a series will be of great service, be- 

 cause the information at present available as to the 

 floras of certain large tracts of India is lamentably 

 deficient. This deficiency Sir George King's in- 

 auguration of a botanical survey of India is calculated 

 to remove. 



For the preparation of the first of the " regional 

 floras " — that of Bombay Presidency — the Govern- 

 ment of India was fortunate enough to secure the 

 services of Dr. T. Cooke. 



To write an ideal " flora " of Bombay is at present 

 impossible. For such a work should not only enable 

 persons to identify plants found in the Presidency, but 

 should also give information as to the geographical 

 distribution of the indigenous species, including their 

 general and local distribution, their habitats, and their 

 frequency of occurrence ; it should also impart inform- 

 ation, often unavailable to the worker in Europe, as 

 to the habits, colours, dates of flowering, of sprout- 

 ing, and of defoliation. Finally, it should give a 

 general account of the whole flora and vegetation of 

 the region, and map out their subdivisions within that 

 region. The present " flora " does not contain all 

 these desiderata, for it is not yet concluded, and much 

 remains to be discovered in regard to the local dis- 

 tribution and periodicity of the Bombay plants. This, 

 the first volume, includes the whole of the Polypetalae, 

 following Hooker's sequence of orders, and the 

 natural order Rubiaceae, 



The characters exhibited by the natural orders are 

 given very fully, so much so that an inexperienced 

 person would find it difficult to decide upon the really 

 salient features. This difficulty might be reduced by 

 printing important diagnostic characters in different 

 type. But when the work is finally complete, the 

 author may aid the tyro by giving abbreviated 

 diagnoses, or possibly an analytical key of the natural 

 orders. 



In describing genera and species of exotic plants 

 the botanist working in a herbarium is often at a dis- 

 advantage. The specimens reaching him are fre- 

 quently comparatively small, their colours are changed. 



