472 SUMMARY OF CURRENT RESEARCHES RELATING TO 



ascogonium two nuclei are visible, which increase to four and eight. 

 After septation, one cell retains two nuclei — the large ascus cell. These 

 two nuclei fuse together as in other asci ; they are probably cousin-nuclei 

 of the second degree. Then the fused nucleus multiplies by division to 

 some 1026. They are so minute that it was impossible to see details, 

 but spindle and diaster were plainly visible, showing the normal mitotic 

 division. 



In spore formation it was noted that there was no previous splitting 

 or division of the plasma as in the Phycomycetes ; the nucleus lay at the 

 apex of the newly formed spore as in other iVscomycetous spores, and 

 between the spores there were remains of the epiplasma ; the spores are 

 therefore the result of free-cell formation. 



The author insists on the Ascomycetous character of the fungus. It 

 differs from Rhyparobius so far that each ascus is the product of a 

 separate ascogonium, but it stands in the same relation to Rhyparobius as 

 Sphcerotheca does to Erysiphe. Also the development is apogamous. 

 As in some other Ascomycetes, sexuality has disappeared. 



Germination of Truffle Spores.* — Em. Boulanger watched the ger- 

 mination of the spores take place in the ascus itself. The brown 

 exospore bursts, generally towards the equator, and becomes destroyed. 

 The spore then puts out a germinating tube. M 



Submerged Fungus.f — H. Rehm describes a Discomycete that he 

 found growing on branches under water. It has been classed by him in 

 the genus Psilopezia, rather than in Humaria or PeUidium in \which it 

 had been placed. The fungus has no marginal wall. 



Yeasts .$ — A. Osterwalder has carried out a systematic examination 

 of fruit and vine yeasts. He examined them microscopically, noting 

 the size and form of the cells, and made cultures of the different species, 

 both streak cultures and giant colonies. He isolated eight different 

 species, and the results of the cultures, fermentations, etc., are recorded 

 in a series of tables. 



Th. Bokorny § has examined the behaviour of various yeasts with 

 regard to colouring matters and metal salts. Yeast cells attracted and 

 stored silver nitrate in extremely weak solutions. Similar results were 

 obtained with copper salts. The quantity of poison required to kill the 

 cells by acting on the protoplasm has not been determined. "With 

 colouring materials, he found that a minute percentage of methyl-violet 

 coloured the cells without injuring them ; a larger quantity coloured them 

 more quickly but finally killed them. 



In another paper || Bokorny gives the results of further work on the 

 growth of yeasts in solutions containing mineral substances, his aim being 

 to determine the nature of the influence exerted by the poison on the 



* C. R. Soc. Biol. Paris, lx. (1906) pp. 42-3 (2 pis.) See also Bot. Centralbl., ci. 

 (1906) pp. 416. 



t Mitth. Bayer. Bot. Gesell., (1905) No. 34, p. 423. See also Bot. Centralbl., ci. 

 (1906) pp. 450-1. 



\ Centralbl. Bakt., xvi. (1906) pp. 36-52 (1 pi.). 



§ A. Br. H. Zeit., Aug. 1905. See also Centralbl. Bakt., xvi. (1906) pp. 257-8. 



|| Wellend. Zeitschr. Spir. Ind., Juli 1905. See also Centralbl. Bakt , xvi. (1906) 

 pp. 239-40. 



