71 



therefore, adopt the term "volutin" as being generally received in 

 the microbiological literature. 



For a detailed morphological description of the volutin-granule 

 I refer to the relative literature^). When fixing moulds or yeast- 

 cells in formol, staining them by methylene-blue and differentiating 

 them in 1 perc. sulpfuiric acid, the cell is decolorized, not however 

 the spots containing the substance called volutin. This substance can 

 be observed as fine granules scattered all over the cells, again 

 coalesced to coarse granules, sometimes imbedded in a vacuole, 

 varying much as to dispersion and quantity. A. Meyer ^), who 

 realized the importance of subjecting to a close microcliemical ex- 

 amination a substance of such frequent occurrence in the vegetable 

 kingdom, has discovered other qualities in addition to the typical 

 colour-reaction just mentioned. If e. g. we treat the methylene-blue 

 preparation thus obtained with a solution of iodine in potassium 

 iodide, the blue granules turn black and gradually lose the colour in 

 5 perc, sodiumcarbonate. The volutin rapidly dissolves in warm 

 water, also in the fresh preparation in 5 perc. sulphuric- or hydro- 

 chloric acid. Tlie digestibility by pepsin could not be made out, 

 since 0.2 perc. hydrochloric acid will throw the substance into 

 solution at bodily temperature. The behaviour of volutin towards 

 dyes induced Meyer to compare it with that of nucleinic acid pre- 

 pared from yeast. He found the one to be very similar to the other. 

 In 190J: Meyer, therefore, advanced the hypothesis that volutin is 

 a nucleinic-acid compound. This view has also been adopted in the 

 later literature on the basis of Meyer's investigation, although Meyer ^) 

 himself became aware that his reactions, from a chemical point of 

 view, were not such as to prove his hypothesis, as witnesses his own 

 pronouncement upon it on page 125, where he positively acknow- 

 ledges that the question as to volutin being a nucleinic acid compound 

 has not yet been set at rest. Still, there was more ground, no doubt, 

 for Meyer's supposition than for Janssens and LÉBtiANCS '), who, ten 

 years before, in their morphological investigation of the nucleus of 

 yeast-cells, consider basophilic granules in the cell-plasma, which 

 they suppose to play the pari of reserve-material, as nucleo-albumins. 



1) Clifford Dobell. Quart, journal of micr. science, 1908, p. 121. 

 SwELLENGREBKL. Arch. f. Hygiene Bd. LXX, 1909, p. 380. 



GuiLLiERMOND. Recherches cytologiques sur les levures etc, These de Paris, 1902. 

 Arch. f. Protistenkunde, Bd XIX, 1910, p. 298. 



Reichenow. Arbeiten aus demkaiserl. Gesundheitsamte. Bd. XXXIli, 1910, p. 1. 



2) 1. c. p. 1. 



s) La Cellule. T. XIV, 1898, p. 203. 



