MYCODERMA. 407 



from samples of soil, and succeeded in bringing about spore- 

 formation by cultivation on gypsum blocks for eight to ten 

 days (the temperature is not mentioned). He also succeeded 

 in causing the spores to germinate in an extract of horse dung 

 with 5 per cent, of grape sugar. It may also be mentioned 

 that J. C. Holm detected lemon-shaped cells, somewhat larger 

 than the ordinary apiculatus cells in certain fermented ciders 

 from England, in the author's laboratory in 1894. By trans- 

 ference to gypsum blocks after a single cultivation in dextrose- 

 yeast water, isolated cells were observed with one or two 

 spores. On account of the extraordinarily small number of 

 spore-forming cells, it was impossible to carry out germinating 

 experiments. By prolonged cultivation and transference of 

 cells to gypsum blocks, to nutritive gelatine, or to small 

 quantities of sterile water, he never again succeeded in bring- 

 ing about spore-formation. During budding, a septum was 

 observed between the mother- and daughter-cell. J. C. Holm 

 assumes that this form is closely related to one of the 8. Lud- 

 wigii (Saccharomycodes Ludwigii), and that possibly the work 

 just mentioned was carried out with such forms, and not with 

 8. apic. Reess. 



Mycoderma cerevisiae and vini. 



It is characteristic of these species that they very readily 

 form films on various alcoholic liquids. Under these names 

 are included a number of different species, some of which may 

 excite a feeble alcoholic fermentation ; they behave differently 

 towards lager beer, some causing disease whilst others do not. 



The Mycoderma cerevisice (Fig. 97) examined by Hansen, 

 which is universally met with in Copenhagen breweries, forms 

 variously-shaped cells. The cells are usually transparent and 

 less refractive than the true Saccharomycetes ; in each cell 

 there are generally one, two, or three highly refractive particles, 

 which often have a quivering, rolling motion. This micro- 

 organism forms a dull, greyish, wrinkled film on wort and beer, 

 and does not excite alcoholic fermentation ; neither does it 

 invert solutions of cane-sugar. 



The colonies on the surface of the gelatine are light grey, 

 dull, and spread out like a film or hollowed like a shell. By 



