106 MICRO-ORGANISMS AND FERMENTATION. 



extent by OicZmm, since it is not able to compete in the 

 struggle with the concourse of organisms which at once 

 appear when fermentable liquids are exposed to the germs 

 of the air. 



In numerous investigations with top-fermentation yeast, 

 I found that this offers a very favourable nutritive material 

 for this fungus, especially when the yeast is in a quiescent 

 state at the end of the fermentation. Sometimes a micro- 

 scopic examination showed an enormous number of conidia. 

 It is not known what influence such a growth exercises on 

 the quality of the yeast and the beer ; without doubt it is 

 advisable to avoid the fungus as much as possible. 



8. C. G. Matthews observed that the red colour which 

 appears on grains of malt, and more particularly when the 

 quality is not very good, is produced by a Fusarium (probably 

 grarfiinearum). He cultivated this mould on various substrata. 

 The fascicular spores are spindle-shaped, curved, and uni- or 

 multi-cellular ; they are colourless, or only very slightly tinted, 

 but were embedded in the preparations in a strongly-coloured 

 mass. The formation of mould commences at the germinal 

 end of the corn, and spreads from thence more or less over 

 the surface. When such corns germinate at all, they show an 

 abnormal development, since they either send out only single 

 rootlets with a sickly appearance, or the plumule only. 

 Whilst the spores of Penicillium^ Mucor, Aspergillus, etc., 

 are easily distributed over the malt heaps by the air, the 

 grains attacked by the Fusarium can, according to Matthews, 

 only communicate the mould to the neighbouring grains, 

 probably because the spores of this mould have a greater weight, 

 and more closely adhere to the original mould-growth than 

 do the spores of the other organisms. 



9. Chalara Mycoderma (Fig. 24) is described in Pasteur's 

 " Etudes sur la biere " as one of the habitants on the surface 

 of grapes. The mycelium forms a film on liquids, and con- 

 sists of branched, greyish filaments, often filled with highly 

 refractive plasma, and which develop at different points conidia 



