40 CYTOLOGY OF YEASTS 



The investigations of Dangeard have shown that the metachro- 

 matic granules are produced from a condensation of a metachromatin 

 matter existing in the vacuole in the state of a colloidal solution. 

 In the living cell they are rather numerous, but staining brings out 

 larger numbers. The metachromatin precipitates under the in- 

 fluence of the vital stains. It acts the same way towards fixatives. 



After fixation by alcohol, the granules are stained more deeply 

 than the nucleus by the nuclear stains. They take the colors of the 

 basic aniline blue and violet dyes and assume a color between a red 

 and violet. With hemotoxyline or hematine they are colored a wine 

 red. This metachromatism, to which they owe their name, distin- 

 guishes closely between the nucleus and other bodies in the cell. 



The metachromatic corpuscles are present in great abundance 

 not only in yeasts but also in many of the Protista. We have shown 

 that they are identical with other bodies which have been observed 

 formerly in the bacteria and Cyanophyceae by Babes and Biitschli, and 

 regarded as grains of chromatin. Biitschli has called them " Red 

 granules " on account of their metachromatism and we have retained 

 by reason of its priority the term " metachromatic granules " sug- 

 gested by Babes. This ought to be used also instead of the term 

 " grains volutine " proposed by A. Meyer. 1 The metachromatic 

 granules have been pointed out, since, in the fungi, algae, and 

 protozoa. On the contrary they do not seem to be present in the 

 Metazoa or the Metaphytes. According to the observations of A. Meyer 

 and Guilliermond, in collaboration with Beauverie, 2 the globoid grains of 

 the Phanerogames contain, associated with glycerol or saccharine 

 phosphates, a nitrogenous substance which seems to be much like 

 the substance which makes up the metachromatic granules. This is 

 metachromatin, more or less like that which is found in yeasts. The 

 granulations of Mastzellen or leucocytes present histo-chemical prop- 

 erties, much like those of metachromatin, as has been pointed out 

 by the investigations of Guilliermond 3 and Mawas. 



There is, then, sufficient evidence for considering the meta- 

 chromatin as composed of nucleic acids. The recent investigations of 

 van Herwerden have given good reasons for favoring this hypothesis. 

 By cultivating yeasts in media completely deprived of phosphates, 

 this author has noticed that these yeasts never contain the least 



1 Meyer, A. Orientierende Untersuchungen iiber Verbreitung, Morph. und 

 Chemie des Volutins. Bot. Zeitg. 62, 1904. 



2 Beauverie, J., and Guilliermond, A. Note preliminaire sur les globo'ides. 

 Comp. Rend. Acad. Sciences, 1906. 



3 Guilliermond, A., and Mawas, J. Caracteres histo-chimiques des granu- 

 lations des Mastzellen. Comp. Rend. Acad. Biol. 64, 1908. 



