THE MOULD-FUNGI. 123 



forming a slimy envelope, which is coloured violet by iodine. 

 The oval conidia germinate either directly or previously grow 

 into sickle-shaped cells consisting of several links. Germinating 

 filaments issue from the points of the latter, and by slow 

 degrees the cells swell up. Both the mycelium and the sickle- 

 shaped conidia are able to produce thick-walled spores. The 

 fungus does not appear capable of hindering the growth of 

 sound malt-corns, even if its mycelium spreads freely over their 

 surface. Generally speaking, it only attacks diseased corns. 



9. Chalara Mycoderma (Fig. 34) is described in PASTEUR'S 

 " Etudes sur la biere " as one of the organisms commonly 

 occurring on the surface of grapes. The mycelium forms a 

 film on liquids, and consists of branched, greyish filaments, often 

 filled with highly refractive plasma, which develop at different 

 points conidia of unequal form and size. CIENKOWSKI, in his 

 memoir on the fungi occurring as films, first gave a detailed 

 description of Chalara. HANSEN found that this mould-fungus 

 develops in both ordinary and diluted wort and lager beer. 



10. A mould-fungus about which a great deal has been 

 written in the literature of our subject is Dematium pullulans 

 (Fig. 35), which was first described by DE BARY, and more 

 minutely by LOEW. It frequently occurs on fruits, especially 

 grapes, and has a branched mycelium, from which buds are 

 thrown out ; these have a striking resemblance to ordinary 

 yeast-cells (4), and are able either to propagate through many 

 generations by yeast-like budding, or to produce germinating 

 threads, which give rise to a mycelium (3). When this has 

 attained a certain age, it forms numerous closely situated 

 transverse septa, and gradually becomes brownish or olive- 

 green (5); in this we have the resting stage of the plant. 

 In a species bearing morphologically a close resemblance to 

 Dematium pullulans a growth of endogenous spores in the 

 filaments was observed by F. WELEMINSKY in the author's 

 laboratory. In HANSEN'S 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. 



