252 HISTORY OF SACCHAROMYCETES IN NATURE. 



with Hansen was that, also in vineyards, the soil forms the normal 

 winter habitat of the Saccharomycetes, and the latter find their 

 way thence to the breeding-place, namely, the grapes. Later on, 

 however, he recognised (LVIII.) that both wind and rain are 

 important means of transport. His experiments with sowing 

 wine yeasts in earthenware pipes showed that the fungi can live in 

 the soil from one autumn to another. Miiller-Thurgau also states 

 that Sacch. ellipsoideus has a very low power of resisting drought, 

 and therefore soon dies when on the surface of grapes exposed 

 to very dry weather and intense sunlight an observation also 

 confirmed by MARTINAND (II.). 



A few years later a thorough investigation of vineyard soil was 

 undertaken by WORTMANN (VI.), with samples taken from the 

 same plot at intervals of 14 days during two years. The largest 

 number of yeast cells was found in November and December ; and 

 must inoculated with the samples of soil quickly began to ferment. 

 During January, February and March fche number of yeast cells 

 diminished ; and during the spring and summer the latter 

 especially the proportion became more and more unfavourable, 

 and the yeasts disappeared from a progressively larger number of 

 the samples. The most unfavourable results were obtained in 

 late summer : August and September ; but from the beginning 

 of the grape harvest the conditions improved almost immediately. 

 Wortmann's conclusion was to the effect that the yeast cells 

 become enfeebled during their sojourn in the soil, most of them 

 dying off; and that the continuation of the species is confined to 

 the few cells that survive the winter and are fortunate enough to 

 find themselves on a damaged grape. As will be evident, 

 especially from what follows, this does not entirely coincide with 

 Hansen's experiments, according to which the conditions in the 

 soil are not so unfavourable for the tiaccharomycetes. With 

 regard to the means of transport, he thinks that Hansen gives 

 undue credit to the wind, his own experiments tending to show 

 that the chief part is played by wasps. 



Whilst both Wortmann and Miiller-Thurgau agree in the main 

 with Hansen's theory on the life history of the Saccharomycetes, 

 the workers named below express a different view on certain 

 points, several of them stating that in hot climates, Italy in 

 particular, the soil is not the chief habitat of the yeast cells. 



BOUTROUX (IX., X.) regards the nectar of flowers, insects, and 

 unripe fruit as constituting the habitat of yeast fungi from the 

 end of winter to the fruit season, and states that the cells are 

 conveyed from flower to flower and from fruit to fruit by insects. 

 It must, however, be remembered that he makes no distinction 

 between Saccharomyces and Torula, but applies the former name 

 to all yeast cells capable of inciting fermentation. Probably, 

 therefore, the cells found by him were not always Saccharomycetes, 

 most of them being certainly forms of Torula, which are widely 



