688 SUMMARY OF CURRENT RESEARCHES RELATING TO 



on the respiration. On older plants there was a marked increase, 

 especially on those cultures where nourishment was scanty. The 

 influence of the light made itself felt in about 30 minutes, but if the 

 plant was exposed to alternate light and dark the effect of the light 

 was altogether feebler. 



Respiration of Fungi.* — S. Kostytschew gives the results of his 

 research on respiration which was undertaken to determine if there 

 were any connection between intramolecular respiration and the alcoholic 

 fermentation of yeast fungi. He experimented with Mucor stolonifer 

 and Aspergillus niger, growing them on various media in an atmosphere 

 free from oxygen. He concludes that intramolecular respiration is not 

 identical with the fermentation process. 



Weather and Parasitic Fungi.f — Karl Sago has collected facts and 

 statistics on the appearance and disappearance during certain seasons of 

 various fungnl diseases, especially those that occur on the vine. He 

 finds that the direction and force of the wind has a great influence on 

 the spread of disease, and that hail showers render the host-plant more 

 liable to attack. More work is required to determine the weather con- 

 ditions that affect special forms. Alternaria solani spread with great 

 rapidity in dry weather that supervened on a rainy season. During a 

 warm damp summer it was noticed that there was very little disease. 



Decomposition of Compounds of Selenium and Tellurium by 

 Moulds. J — 0. Rosenheim gives a resume of his results which confirm 

 those recently published by Maassen. The biological test for arsenic 

 onsists in the formation of gaseous organic arsenic compounds with a 

 characteristic garlic odour produced by the growth of certain moulds 

 (Aspergillus, Penicillium, Mucor) in media containing arsenic. "When 

 applying this test to beer and sugar which contained selenium and 

 arsenic, the author noticed a pronounced faecal odour different from 

 that produced by arsenic alone. Experiments with soluble selenium 

 compounds showed that this was due to the presence of selenium. It 

 was also found that tellurium compounds were decomposed by Peni- 

 cillium brevicaule, producing a very characteristic odour. The odour 

 produced by decomposition of selenium compounds is very disagreeable, 

 being something like skatol or mercaptan, whilst the gases formed by 

 tellurium compounds have a strong garlic odour. The test is extremely 

 sensitive; 0*01 mgrm. in 1 ccm. oi liquid is easily demonstrated by a 

 vigorous growth of the mould. Unlike arsenic, pure selenium aud 

 tellurium are not attacked by the mould. 



Influence of Sulphocyanic Acid on Growth of Aspergillus 

 niger.§ — A. Fernbach finds that the presence of sulphocyanate of 

 ammonia in a liquid in which the mould is growing has no sensible 

 effect on the development of the mycelium, but causes arrest of the 

 fructification which only begins to develop when the sulphocyanate has 

 disappeared, probably as a result of oxidation. This effect is remarkable 

 as it is contrary to what -we might expect from the general behaviour of 



* Eer. Deutsch. Bot. Ges., xx. (1902) pp. 327-34. 



t Zeit. Pflauzenkr., xii. pp. 151-7. 



% Proc. Chem. Soc, xviii. (1902) pp. 138-9. 



§ Comptes Rendus, exxxv. (1902) pp. 51-2. 



