420 MYCODERMA. 



water, the last-named sugar is attacked first, the disaccharides 

 not being degraded at the start. No invertase or maltase could 

 be detected in the Mycoderma cells. The saccharose and maltose 

 were oxidised direct to water and carbon dioxide. Finally, 

 Meissner's Mycoderma species, which were grown on sterile grape 

 juice, partly oxidised dextrose and Isevulose, but also formed 

 acids from these sugars. On artificial nutrient solutions, con- 

 taining dextrose or saccharose as the sole organic substance, in 

 addition to the requisite mineral food-stuffs, the Mycoderma 

 oxidised the sugars, though utilising a portion of the same in 

 the formation of new cells, and also forming acids therefrom. 

 Mycoderma lebenis, RIST and KHOURY (I.), grew admirably well 

 in glucose and maltose, the glucose being transformed into acid 

 and the alcohol oxidised. 



According to further researches by MEISSNER (VII.), glycerin 

 and tannin are also consumed by Mycoderma in the same way as 

 alcohol, acids and sugars. A species of Mycoderma found by 

 EITNER (I.) on mimosa bark also decomposed tannin. 



Mycoderma species, however, in addition to decomposing 

 glycerin, are also capable of forming the same from other organic 

 substances. W, SEIFERT (II.) reports that his Mycoderma vini I. 

 produced 0.152 per cent, of glycerin in Pasteur's nutrient 

 solution by the end of 14 weeks, the whole of the alcohol having 

 disappeared. Mycoderma vini II. , on the other hand, formed 

 only o.o 1 6 per cent, of glycerin, the alcohol diminishing con- 

 currently from 4.8 to 4.1 per cent, by volume. 



308. Influence of other Factors on the Vitality of 

 Myeoderma. 



Highly interesting observations of the longevity of Mycoderma 

 in wort cultures and in the dry state were made by WILL (XIII.) 

 Cultures that had been stored for 4^ years in wort were found tc 

 contain living cells when re-inoculated in fresh wort, thui 

 demonstrating the longevity of Mycoderma cells in wort. Wil 

 also showed that Mycoderma can survive for a long time in a dry 

 state at least two years in the case investigated by him. Low 

 temperature favours the maintenance of vitality in the dry state 

 and the content of water in the dried cells probably also plays a 

 principal part. 



WILL (XIII.) also investigated the power of old and young 

 Mycoderma cells to resist the action of heat in liquids, the heating 

 being applied in water, then in wort and finally in sauerkraut 

 water. The cultures were of various ages. The duration of 

 heating was half an hour, not reckoning the preliminary warm- 

 ing. The results showed definitely that the degree of resistance 

 offered by the cells is influenced by the character of the substratum. 

 For the species under examination, the critical temperature in 



