254 HISTORY OF SAOCHAROMYCETES IN NATURE. 



unconditionally applicable to the true Saccharomycetes. Thus, in 

 his researches in the German wine districts, he found that at 

 certain periods the samples of soil from the vineyards contained 

 fewer yeast cells, and also wine-yeast fungi, than similar samples 

 from adjacent meadows. Indeed some 5QJC.C. samples of vineyard 

 soil did not contain a single living cell tKal coulS" be identified 

 as Sacch. ellipsoideus. Analogous, though scarcely so extensive, 

 irregularities occurred in certain analyses of orchard and arable 

 soils in the vicinity of Copenhagen. Consequently, HANSEN (LX.) 

 was led to extend his researches and proceed in a different 

 manner, the methods being made more stringent, the number of 

 the analyses greatly increased, and the area of the experiments 

 broadened to comprise an enormous district, from Scandinavia 

 to southern Italy, from the plain to the highest mountain top. 

 The principal new direction taken by these experiments was, 

 however, the investigation of the secondary habitats. The 

 analyses of soils from round Copenhagen showed that true 

 Saccharomycetes are to be found everywhere in the soil all the 

 year through, even in places where Sacch. apiculatus is only 

 detected occasionally if at all, that is to say, at considerable 

 distances from fruit gardens. Only when the number of analyses 

 had reached sufficient dimensions did it appear that the garden 

 soils are the richest in Saccharomycetes, and that the number of 

 the cells diminishes as the distance from these centres increases. 

 For instance, in a series of 200 analyses, true Saccharomycetes 

 were found in 67 per cent, of samples of soil taken from under 

 fruit trees and fruit bushes ; in 30 per cent, of those from under 

 deciduous and coniferous trees in the vicinity of fruit gardens, 

 and only on 19 per cent, of samples from distant fields. Similar 

 results were obtained in the experiments conducted in mountain 

 districts, e.g., the Hartz Mountains and the Alps. The greater 

 the altitude and the distance from fruit gardens, the less plenti- 

 fully are Saccharomyces cells found in the soil. Hansen's newer 

 analyses show that the parallel also holds good in warmer climates, 

 e.g., Italy. 



The reason of the presence of Scuccharomycetes at considerable 

 distances from fruit gardens and primary breeding-places in 

 general is in part traceable to the fact that their power of pro- 

 ducing endospores makes them better fitted than Sacch. apiculatus 

 for resisting drought. On the other hand, it is to some extent 

 due to their higher capacity for reproducing in nature in numerous 

 secondary breeding-places, apart fro'm the primaryl ones (sweet, 

 ripe fruit), the latter, moreover, being located in woods and other 

 places, and not merely restricted to gardens and vineyards. Such 

 secondary breeding- places are formed by the liquid matters of the 

 soil, i.e., organic extracts of animal and vegetable substances, 

 manure, &c. True, the reproduction effected in this way is very 

 small in comparison with that of the primary breeding-places, and 



