202 SECTIONAL ADDRESSES 



own special yeasts for inoculating the wort. These give the slightly 

 different, well-known characteristics associated with the names im- 

 mortalised by Calverley : ' O Beer, O Hodgson, Guinness, Allsopp, Bass ! 

 Names that should be on every infant's tongue ! ' Pure cultures of 

 bottom yeasts used for light beers are maintained fairly easily in an 

 uncontaminated condition. Top yeasts are more liable to be mixed 

 with foreign or wild yeasts, which are deleterious and give rise to ' disease,' 

 though certain non-sporing yeasts are frequently associated with the 

 conditioning of English bottled beers. 



K. Kruis and J. Satava working in Czeckoslovakia in 1918 showed 

 that there was an alternation of generations in yeasts and regarded 

 Torula and other non-sporing yeastsas haploid forms. Little notice was 

 taken of their work, but recently O. Winge, of the famous Carlsberg 

 Laboratories, has independently confirmed some of their results. The 

 difference in haplophase and diplophase is remarkable in some fungi, 

 as for example in Ustilago laevis and U. Hordei, where the unfused conidium 

 is unable to infect the host plant. We may anticipate some similarly 

 distinct physiological differences among the yeasts. 



The art of distillation for the preparation of beverages apparently 

 dates back as far as 2000 B.C., and St. Patrick is reputed to have taught 

 it to the Irish. Whisky and gin are prepared from barley in a manner 

 similar to beer. The malt, however, is left until the whole of the dextrin 

 is converted into maltose, so that in subsequent fermentation by yeast 

 the maximum amount of alcohol is produced. The strains of yeast 

 employed have a high fermentative power. 



To turn for a moment to the fuel problem which is becoming of 

 increasing significance. It has been estimated that English coal will 

 be exhausted in four hundred years, and that of the United States in 

 four thousand years if there is no increase in its consumption ; whereas 

 if the rapid increase of the recent past is continued these periods will be 

 reduced to fifty and five hundred years respectively. Although petroleum 

 is an obvious substitute, the supply of this is doomed to suffer through 

 modern excessive use. Consequently other fuel sources have been 

 suggested, but the future doubtless lies with power alcohol to be obtained 

 from plant materials, either cellulose, sugar or starch. Alcohol is one 

 of the most important chemicals, and its cheap production is absolutely 

 essential for the development of many new industries. In the preparation 

 of industrial alcohol, sugar-beet, beet- or cane-molasses, potato, maize, 

 rice or similar starchy materials are used. The old process resembles 

 that for the production of potable spirit, but the ingredients are inferior. 

 The propagation and culture of the yeast is the most important step in 

 the process. The aim is to have sufficient active pure yeast so that the 

 fermentation can proceed rapidly ; distillation is carried out so soon as 

 the fermentation is complete, and this prevents the loss of alcohol — the 

 yeasts tend to overgrow all other organisms so long as sugar is present. 

 The carbon dioxide obtained as a by-product is now employed to prepare 

 ' Dry Ice ' for refrigeration processes. 



The method of converting starch into sugar in the malting operations, 

 however, is not entirely satisfactory, and recourse has been had to 



