204 SECTIONAL ADDRESSES 



fermentation has been regarded until recently as the perquisite of fungi, 

 but Lindner has isolated a bacterium from pulque, Termobacterium mobile, 

 which provokes a reaction very closely resembling pure alcoholic fer- 

 mentation. Pulque is very like sour milk in flavour, and is much esteemed 

 for its cooling properties, though the natives also regard it as nutritious. 



Other fermented liquors which appear to owe their main characteristics 

 to yeasts are Taette, a thick viscous non-coagulated milk product with 

 an agreeable acid taste, known in Scandinavia from antiquity ; Bid, a 

 wine of West Africa prepared from the tubercles of Osbeckia grandiflora ; 

 Sorgho, an alcoholic drink of Manchuria, made from Sorghun saccharaturn, 

 and Nigger beer of East Africa from millet. 



Probably few of the drinks prepared in a more or less casual manner 

 so far as concerns the essentials of the process — though special rites may 

 attend their preparation — owe their alcoholic properties entirely to one 

 organism. Sometimes allied species take part in the general mass-action 

 in a manner similar to that in which wild yeasts sometimes enter into the 

 fermentation of beer-wort ; often doubtless some of these foreign organisms 

 interfere with the normal process. 



Apart, however, from these casual associations which may work in 

 harmony or antagonistically, there are several fermented drinks, some very 

 ancient, which owe their properties to the regular association of two or 

 more organisms. 



One of the best known of these is the old English Ginger Beer ousted 

 to a great extent by the manufacturer, who either allows natural fer- 

 mentation to take place, or adds brewers' yeast : the so-called ginger 

 beer of the aerated water type is entirely different. The ' ginger-beer 

 plant,' however, becomes widely known at times. Immediately after 

 the War it was to be obtained all over the country as Californian 

 Bees, American Bees — and as the generally accepted belief was that it 

 had been brought home by soldiers on active service — Macedonian Bees, 

 Jerusalem Bees, and so on. Professor T. G. B. Osborn tells me that 

 it is often sold by pedlars in Australia. The plant is a globular white 

 mass usually about the size of a pea, and is used for fermenting a sugary 

 fluid. The production of carbon dioxide causes the mass to rise to the 

 surface of the liquid, and it settles down again after the liberation of the 

 gas. There is thus a constant slow up-and-down movement which 

 during the last epidemic was the cause of considerable interference with 

 what Peacock calls ' the honeyed ease of the Civil Servant's working 

 day ' — at least for one. The constituents of the mass are a yeast 

 (Saccharomyces pyriformis) and a bacterium {Bacterium vermiforme) ; the 

 bacterium has a pellucid, swollen, glutinous sheath, and the yeast cells 

 appear to be mechanically entangled in the matrix of coiled filaments. 

 Other organisms are frequently present but are not regarded as essential. 

 The yeast works more efficiently in the presence of the bacterium which, 

 moreover, apparently also aids by preventing the products of fermentation 

 from reaching the yeast, possibly by destroying some of them ; the 

 products are different from those when each organism acts alone — large 

 quantities of carbon dioxide, lactic acid, and little or no alcohol. It is 

 not unlikely that the ginger-beer plant arose as a contamination of raw 



