336 SUMMARY OF CURRENT RESEARCHES RELATING TO 



these same bodies which he has termed metachromatic corpuscles. The 

 yeast of Oidium was multi-nucleate. In the true yeasts he describes the 

 same structures ; the small nucleus (Wager's nucleolus), consists of 

 colourless nucleoplasm, a nucleolus, and a surrounding membrane. It 

 is connected with the vacuole, he considers, only because the cell is 

 small and the contents necessarily lie close together. When budding 

 takes place, the vacuole passes partly into the new cell and divides, but 

 quite independently of nuclear division. The later takes place as typical 

 amitosis. In some cases the nucleus elongates, penetrates the new cell, 

 and then divides ; in other cases it divides without any perceptible 

 stretching, and one of the two resulting nuclei travels into the daughter- 

 cell. 



In addition to the vacuole with metachromatic corpuscles, he found 

 in the yeast-cells vacuoles filled with glycogen. These were most 

 prominent during active fermentation, almost filling the whole cell. 

 As fermentation declines, the glycogen tends to disappear, and the 

 corpuscular vacuole takes its place. Wager had already noted this 

 peculiarity and distinguished them as nuclear and glycogen vacuoles. 

 Guilliermond considers that the granulations are of the same nature as 

 the metachromatic corpuscles of bacteria. A careful account of the 

 methods of preparation, staining, &c. is given. 



In a further communication, he describes the phenomena accom- 

 panying fusion and spore-formation in three species of yeast. He finds 

 in them a true isogamous conjugation which precedes the formation of 

 the ascus and concludes therefore that the ascus is a zygote. 



In another paper,* the same writer gives in detail the process of 

 spore-production in Saccharomyces Ludwigii. Hansen had already noted 

 the peculiar germination of this species by means of a promycelium after 

 fusion of two spores. Guilliermond verified Hansen's results, and gives 

 an account of the formation of the germinating tube or promycelium, 

 and of the previous spore-fusion. In some cases, when growing on 

 carrot, the fused body formed an ascus immediately, containing 4 spores. 

 Usually the ascus was formed from part of the promycelium. He also 

 was able to observe the fusion of the nuclei of the two conjugating 

 spores. The writer discusses the systematic position of this yeast and 

 considers that it ought to be separated from Saccharomyces and placed 

 under another genus or sub-genus. The paper is well illustrated by a 

 plate and by numerous figures in the text. 



Formation of Yeast-Spores.| — Chr. Emil Hansen has succeeded in 

 inducing the formation of spores in the yeast-cell without any inter- 

 vening vegetative development or any previous fusion of cells. He 

 grew the yeast Johannisberg II. in a film of water, then in a film of 

 wort. They were again transferred to a solution of calcium sulphate 

 which stopped the process of budding, but not that of spore-formation. 

 After 3-G days it was found that the spores had become spore-mother- 

 cells, and that spores were formed inside them. Two illustrations 

 accompany the paper. 



* Bull. Soc. Myc. de France, xix. (1903) pp. 19-33 (1 pi.). 



t Compte-rendu des travaux du laboratoire de Carlsberg, v. (1902) livr. 2. See 

 also Centralbl. Bakt., x. (1903) p. 125. 



