ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 591 



Prostemiella, Psammina, and Pcstalozzina belong to the Hyalophragmise. 

 A beginning has also been made with the Phseophraginiae. The genus 

 StiJbospora is completed, and a few of the species of Coryneum. The 

 genera are well illustrated. In the small genus Thyrsidium there are 

 drawings of no fewer than four species. 



Yeasts.* — G. Marpmann confirms Wager's results as to the pre- 

 sence of nuclei in the cells of yeast. He gives a careful account of his 

 methods of fixing and staining for determining the presence of nuclei. 

 He has applied the same treatment to the larger bacteria and has proved 

 the existence of nuclei in their cells also. He gives, further, an 

 account of his prolonged cultures of yeasts, and recommends nuclei- 

 staining as a help to diagnosing the different species. Wild yeasts, he 

 finds, grow at a lower temperature than the forms under cultivation, but 

 in time they develop into culture yeasts. As yeasts differ in form, 

 contents, nuclei, &c, so do they differ probably in the results they 

 produce in the fermentation process. He gives a list of the Saccharo- 

 myces species he has studied. The different forms are classified as 

 white, grey, yellow-brown, yellow, red, and black yeasts. The writer 

 gives also some account of his work on Schizcsaccharomyces. 



Observations on the Vitality of the Yeast Plant.f — H. Will has 

 found that after 15 years and 2 months yeast-cells developed from the 

 charcoal and asbestos used in connection with brewing. Cells of wild 

 yeast were also frequently found, especially in the asbestos. The vitality 

 of wild yeast is very great when unfavourable conditions such as high 

 temperature, &c. are excluded, and the experiments made prove the 

 great risk of infection from that plant in the brewing process. 



Smut of Cereals. J — Tubeuf gives the results of many experiments 

 undertaken with a view to further our knowledge of the fungus 

 causing smut and the best means of combating the disease. As a 

 method of prevention he recommends treating the seed with Bordeaux 

 mixture. In order to test predisposition to disease, eight varieties of 

 maize seed were dusted with smut spores before being planted. The 

 results as to infection were very varied, and the experiment is still 

 being carried on. 



The writer states, among other interesting results, that infection does 

 not take place through wind-borne spores. He finds also that the spores 

 of Tilletia cannot persist during winter in the soil and that they are 

 harmless for horses, cattle, sheep, and pigeons. Low temperatures are 

 unfavourable to the development of the fungus, so that to delay sowing 

 corn until the season is advanced is to increase the risk of disease. 



Biological Phenomena in the Cultivation of Ustilago Maydis.§ — 

 When spore-formation takes place in Ustilagn Maydis, the spore-forming 

 hyphre become mucilaginous. J. Griiss has investigated this in order 

 to determine the possible presence of an enzyme. He finds, after long 



* Zeitschr. angew. Mikr., viii. (1902) pp. 57-62. 



t Zeitschr. ges. Brauerw., xxv. (1902) pp. 49-50. See Centralbl. Bakt., 2 Abt., 

 ix. (1902) p. 69. _ . _ ., .. .. 



t Arb. aus biolog. Abt. fur Land- u. Forstwirtlisch. am Kais. Gesundheits , 11. 

 (1902) pp 179-349 ( 1 pi. and 19 figs.). See also Bnt. Zeit, lx. (1902) pp. 204-5. 



§ Ber. Deutsch. Bot. Ges., xx. (1902) pp. 212-20 (1 pi.). 



