74 



NATURE 



[May 24, 1900 



expressed, and are in the main in touch with the teachings 

 of modern sanitarians. 



It is to be regretted that in this chapter the author 

 allows his personal antagonism to Koch's doctrine of 

 disinfection to weaken his arguments and conclusions. 

 That the followers of Koch sometimes carried disinfection 

 too far does not detract from the value of Koch's original 

 observations. 



Prof. Hueppe lays peculiar stress on the importance of 

 making infectious disease impossible by removing the 

 predisposition to disease, but he scoffs at the idea of 

 combating disease by warring directly with the germs of 

 disease. Although there is a great deal to be learnt from 

 this chapter, it seems a pity that so able a writer should 

 have marred his own work by a captious criticism of 

 Koch's able investigations. 



The last chapter (pp. 440-455) deals with the " History 

 of Bacteriology." Ably written though it is, it, like the 

 first chapter, appears to be foreign to the general scope 

 of the book. 



In summary of the book as a whole, it may be said 

 that it affords more ground for serious thought and 

 reflection than perhaps any of the works on bacteriology 

 hitherto published. The original and able manner in 

 which the author attacks biological problems of great 

 difficulty and complexity deserves all praise, and we can 

 cordially recommend the book, not only to bacteriologists 

 pure and simple, but also to those physicians who recog- 

 nise the limitations of medical science. 



Much praise is due to the translator. Mr. Jordan's 

 worth as a bacteriologist is well known and fully appre- 

 ciated. By giving us this translation of Hueppe's work 

 he has added to his reputation. A. C. Houston. 



SUNSHINE AND WINE-GROWING. 

 Vinificatton dans les Pays chatcds — Algcrie et Tunisie. 

 Par J. Dugast. Pp. 281 ; 58 figures. (Paris : Carre 

 et C. Naud, 1900.) 



ACCORDING to the preface, valuable scientific and 

 technical works on the production of wine in tem- 

 perate climates have been published both in France and 

 elsewhere ; but so far the special problems which are 

 encountered by wine-growers in the warm climates of 

 such countries as Algeria and Tunis have remained un- 

 noticed. The present work is intended by the author 

 to fill this blank. But although it has been written 

 specially with a view to describe the difficulties peculiar 

 to wine-making in a warm climate and the means of over- 

 coming them, the author has done more than this, for he 

 has found it advisable, in order to make his purpose 

 quite clear, to embody his special subject in a general 

 scientific and technical description of wine-making. As 

 he has had very considerable practical and scientific 

 experience in his subject, the result is a work well worth 

 the attention of all interested in the making of wine. 



The most common difficulty of the Algerian wine- 

 grower, and one which is very rare in the more temperate 

 climate of France, is due to the must, or grape juice, 

 very frequently containing too little acid and too much 

 sugar as a result of very active plant assimilation induced 

 by excessive solar radiation. Deficiency of acid is apt 

 NO. 1595, VOL. 62] 



not only to affect injuriously the flavour of the resulting 

 wine, but also to induce unsoundness ; the latter effect 

 being caused by the low acidity of the wine favouring 

 the growth of injurious bacteria, which the higher acidity 

 of a normal wine tends to inhibit, owing to the well- 

 known fact that an acid medium is unfavourable to the 

 development of most ferment bacteria. 



The means employed to remove the difficulty of want 

 of acidity, which are described by the author, let us into 

 secrets of wine-making which some may perhaps be in- 

 clined to think border on sophistication. Plastering is 

 one which is undoubtedly objectionable. It consists in 

 adding calcium sulphate to the crushed grapes, which 

 results in the formation, from the cream of tartar present 

 in the must, of sulphate of potash. But this method, 

 though evidently made use of by many wine-growers, is 

 condemned by the author, and also discouraged by the 

 French law, which limits the amount of sulphate of potash 

 to two grammes per litre. 



Other methods for increasing the acidity of the must 

 are : crushing a certain quantity of unripe sour grapes 

 with the ripe ones ; the addition of tartaric acid to the 

 must previous to fermentation ; and sprinkling the grapes 

 in the wine-press with, what the author styles, di-calcic 

 phosphate. The latter treatment is said to result in the 

 formation of acid phosphate of potash, a salt considered 

 by the author to be less objectionable than sulphate of 

 potash. 



Excess sugar in the must acts detrimentally by throw- 

 ing too much work on the yeast, which is itself apt to 

 be crippled in the hot climate of Algeria by an exceed- 

 ingly high fermentation temperature. Mention is made 

 of the fermentation temperature at times rising to up- 

 wards of 115° F. — which in itself is sufficient to arrest 

 the fermentation functions of most yeasts. 



About 20 per cent, of sugar is considered the most 

 favourable amount for a wine must to contain, and if the 

 saccharometer shows that 'it exceeds this amount, the 

 best remedy appears to be the simple and inexpensive 

 use of the pump. 



An interesting point, about which much has been said 

 of late years, is raised by the author when he deals 

 with the question of the use of pure selected yeasts in 

 the fermentation of wine. It has been advanced by cer- 

 tain upholders of this system that the characteristic 

 flavour or bouquet of most well-known wines is produced 

 in the main by the variety or species of yeast natural 

 to the grapes of the district, and that, if pure cultures 

 of such yeasts are made use of in the fermentation of 

 foreign musts, the flavour of the resulting wines assume 

 the character of the wines of the district from which the 

 yeasts were obtained. 



The idea is evidently one of the greatest importance 

 to the wine industry, as it holds out hopes of improving 

 the wine of poor districts into something like, let us say^ 

 first quality clarets or Burgundies. The author of this 

 book states that selected yeasts have been much used 

 by the wine-growers of Algeria, and he claims to have 

 had ample opportunities for studying the results. The 

 conclusion he arrives at is that the yeast from a noted 

 growth of wine, when added to an ordinary must, is 

 quite powerless to confer on it the special qualities of 

 the wine from which it comes ; and he further concludes 



