416 MYCODERMA. 



The colour of the film also varies with the stage of growth 

 and with the race. While the film is still quite thin, it has no 

 particular colour, only a few spots (as already mentioned) showing 

 up white. These are the places where the film has already become 

 somewhat thicker and contains a good deal of air enclosed between 

 the individual cells. In proportion as folding (i.e., cell growth) 

 progresses, the colour turns white at first, owing to the inclusion 

 of air ; and when the film has thickened, it becomes whitish grey, 

 whitish yellow, whitish violet-green, violet, yellow, yellowish red, 

 and so on. In some species a very thick film is produced, in 

 others it remains thin, the rugous films being usually the thickest, 

 and the more finely wrinkled forms correspondingly thinner. 



With regard to the attendant phenomena in connection with 

 the production of films, when the latter are formed on a nutrient 

 liquid the latter may either remain limpid or become cloudy after 

 a time, or else cloudiness may set in as the film is being formed. 

 The cloudiness is due to the Mycoderma species concerned forming 

 loose bud aggregations, the cells of which are readily detached 

 and dispersed throughout the liquid, and the degree of cloudiness 

 depends on the extent to which this dissemination can take place. 

 In the case of certain species of Mycoderma, the detaching of the 

 cells does not occur for some little time ; and here, again, we meet 

 with two well-defined types: either (i) large masses, or (2) small 

 aggregations of buds, being detached from the film. On reaching 

 the bottom of the culture vessel, the Mycoderma cells do not perish 

 immediately ; in fact, they are very tenacious of life, and put 

 forth fresh bud cells from time to time. WORTMANN (XVII.) 

 succeeded in isolating living Mycoderma cells from wine that had 

 lain in bottle for 25-33 years, tightly closed with the original 

 corks. 



The starving cells at the bottom of the culture vessel may 

 also be carried up again into the liquid by the gas bubbles rising 

 from time to time from the deposit. These cells, being in an 

 emaciated condition, are but little heavier, specifically, than the 

 surrounding liquid, so that the latter occasionally remains 

 cloudy for some considerable time. 



When Mycoderma species are grown on grape juice or wort, 

 the liquid may be decolorised thereby (see p. 395, vol. ii.). This 

 was observed by WILL (XIII.) in the case of beer wort, and con- 

 firmed by MEISSNER (XI.) in the case of grape juice. The latter, 

 however, observed that the pale yellow colour of grape juice may 

 turn to a dark brown when this juice serves as a habitat for 

 certain races of Mycoderma, owing to the formation of alkaline 

 substances which neutralise the acids in the juice and finally 

 render the liquid alkaline. -\_ 



