178 CHEMISTRY OF THE YEAST CELL. 



gypsum blocks for the purposes of spore analysis (§ 247) ; and a 

 similar gelatinous network is often observable in yeast samples 

 (about the size of a pea) that have been taken by the brewer 

 and dried between blotting-paper in order to be conveniently 

 sent by post to a laboratory for examination. Their detection 

 is facilitated by the aid of staining, either with Methyl Violet, 

 which stains the cells only (Fig. 167), or by the so-called capsule 

 staining method (§ 33) described by Hansen (XVI.). The latter 

 method stains only the mucinous network, and thus renders the 

 latter visible in cases where it could not be detected in the un- 

 stained preparation. It sometimes happens that, during the 

 preliminary treatment of the sample of dried cells to be stained, 





Fig. 157.— Network in Carlsberg Bottom-fermentation Yeast No. i. Hansen. 



The majority of the cells have been washed out of the network in the course of 

 staining with ^Methyl Violet, only thirty-one cells being left. These, having been deeply 

 stained, have a dense black appearance in the Fig. Magn. 1000. {After Hansen's 

 original draivings.) 



the cells themselves get washed out of the network, thus leaving 

 the latter isolated and empty. Fragments of evacuated net- 

 work are not infrequently observed (Fig. 158). I^eveitheless, it 

 should not be assumed, without further inquiry, that every 

 formation with this appearance is a residue of this kind ; but 

 one miist bear in mind the observation made by H. Will (VII.) 

 to the effect that the glutin bodies present in sedimental yeast 

 frequently exhibit, when dried, an appearance resembling frag- 

 ments of the network in question. In such cases, decisive 

 information is afforded by an addition of acetic acid to the 

 preparation, this acid dissolving only the remains of the glutin 

 bodies. Will has also shown that several different kinds of 

 reticulation, and substances composing same, are found in the 

 films and yeast ring of wort cultures of beer yeast. This 

 matter will be reverted to in the next paragraph. 



