THE MOULD-FUNGI. 109 



septa, and gradually becomes brownish or olive-green (5) ; in 

 this we have the resting stage of the plant. In Hanserfs 

 air-analyses Dematium was very frequently found, from 

 spring until late autumn, in wort to which the air had access ; 

 he observed that when the mould was sown in a saccharine 

 liquid, it at first only developed mycelial threads ; after some 

 time, however, the yeast-like cells were separated, without 

 inducing alcoholic fermentation. Pasteur has very fully 

 treated of this organism in his " Etudes sur la biere." Since 

 it occurs so abundantly on the surface of grapes, where the 

 wine-yeast is developed, and since this often has exactly the 

 same appearance as the yeast-like cells thrown off by Dema- 

 tium, it might be imagined that the conidia of the latter 

 were identical with the wine-yeast cells (Saccharomyces). 

 In different parts of the above-named work Pasteur expresses 

 himself differently on this point ; in certain relations he only 

 puts forward this connection as a supposition, whilst in other 

 places he regards it as a matter of fact. Here again we 

 have an example of the attempts previously mentioned to 

 connect the yeast-fungi (Saccharomycetes) with the mould- 

 fungi. According to the present methods of research, the 

 question no longer admits of doubt. The true wine-yeasts 

 can, under certain conditions, which have now been thoroughly 

 investigated, produce spores in their interior ; under the same 

 conditions the conidia of Dematium develop no spores, 

 and are thus distinguished from the wine-yeast. 



1 1 . Finally, we have to mention a mould which may occur, 

 for example, in fermentable liquids and in fermenting rooms, 

 Cladosporium herbarum. This organism sometimes occurs 

 in very large quantities in fermenting rooms ; some years 

 ago I found, in a bottom-fermentation room, the ceiling and 

 a portion of the walls thickly covered with small black 

 patches ; these consisted of this mould, whose conidia I 

 consequently always found in the yeast. The plant consists 

 of a yellowish-brown mycelium, with short, straight, stiff, 

 and brittle filaments, of which those growing erect can produce 



