ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 509 



There is a loose tangle of hyphae in the hypothecium, each cell contain- 

 ing one, two, or several nuclei. Certain of these nuclei fuse in pairs, 

 and the cells in which they occur produce the ascogenous hyphae. The 

 characteristic crozier is formed with a terminal uninucleate cell and a 

 penultimate binucleate cell, from which the ascus arises. Occasionally 

 the end cell fuses with the stalk and forms another ascus. Evidence 

 was obtained that mitosis shows two chromosomes in the vegetative 

 hyphae and four in the ascogenous hyphae. On the formation of the 

 ascus a second fusion takes place, the chromatin of the nuclei remain- 

 ing distinct until the spireme stage. Division of the ascus nucleus for 

 spore formation takes place, and the writer holds these two constitute a 

 meiotic phase. Extrusion of chromatin bodies was observed ; the spireme 

 thread showed longitudinal duplication. A certain amount of contrac- 

 tion then takes place ; afterwards the thread loosens out again, and finally 

 breaks up into four gemini. A final contraction takes place when the 

 chromosomes pass on to the spindle. In the first two divisions there are 

 four chromosomes on the spindle ; the third division is brachymeiotic ; 

 there are four chromosomes in the prophore, only two passing to each 

 pole. 



Mushroom Poisoning.* — J. Dearness writes on the personal factor in 

 poisoning due to eating fungi, and calls attention to the fact that many 

 people find that certain articles of diet, wholesome usually, are more 

 or less poisonous for them. There are these dietetic idiosyncrasies 

 that apply to fungi as to other articles of food. Again, he states that 

 imagination may have a good deal to do with severe poisoning, a slight 

 indigestion being magnified to a serious illness. Besides these cases, 

 the fungi may be too old, or too long gathered. He gives instances 

 of poisoning to support these statements, and concludes that it is risky 

 to recommend fungi as a diet to the uninitiated. 



Yeast-cells and Fermentation. f — Harold Wager read a paper on 

 the yeast-cell before the Institute of Brewing ; he described the struc- 

 ture of the cell and the form of the nucleus, with its large vacuole, 

 and explained the methods used to examine the cells under high powers 

 of the Microscope. The yeast-cell contains glycogen, which increases 

 as fermentation proceeds ; and as a result of the great quantity of 

 glycogen produced, fermentative activity ceases and the cell sinks to the 

 bottom of the liquid. After a time the glycogen decreases, the cells rise 

 to the surface, and fermentation begins again. 



Study of Fungi imperfecti.J — H. Leininger selected for culture- 

 experiment a species of Pestalozzia which grew on dead branches of 

 Mesembryanthemum and Echeveria, and which agreed with the descrip- 

 tion of Pestalozzia palmarum Cooke. As a result of his cultures he 

 finds : — 1. P. pcdmarum produces similar spores in pycnidia, in pseudo- 

 pycnidia, in layers and singly on hyphse. 2. The surest method of 

 producing pycnidia is to withdraw nourishment from the mycelium 

 developing in culture solution. 3. Pseudopycnidia are produced in the 



* Mycologia, iii. (1911) pp. 75-8. 



t Journ. Inst. Brewing, xvii. (1911) pp. 2-15. 



J Centralbl. Bakt., xxix. (1911) pp. 3-35 (14 figs.). 



An//. 16th, 1911 2 L 



