ZOOLOGY AND BOTANY^ MICROSCOPY, ETC. 253 



and besides is washed with a shower-bath of sodium chloride. The 

 researches have thus clearly shown of what importance pure air is to 

 the process of fermentation. 



With regard to the limits of the species of Saccharomyces ; it has 

 been shown that there is a group, which after it has undergone a 

 certain more or less weakening treatment, has a tendency to form 

 elongated instead of oval cells when introduced into a favourable 

 nutrient solution. On the other hand, there are some which in the 

 process of weakening itself form elongated cells. The different 

 species behave differently during this process. The time occupied in 

 similar modes of cultivation up to the formation of the so-called 

 ascospores is likewise an important guide in the discrimination of 

 the different forms. In this cultivation temperature plays an im- 

 portant part, though not so important as Eeess has stated; low 

 temperature for instance is not favourable, but rather checks develop- 

 ment. The maximum, best, and lowest temperatures also vary for the 

 different species. 



The inverting power of fungi is not so universal as was 

 formerly supposed ; and this and the power of alcoholic fermenta- 

 tion may be combined in various ways in the different fermenting 

 organisms. 



Finally, with regard to Oiclium lactis and Chalara ; the small yeast- 

 like cells which Pasteur calls Torula were carefully studied; with 

 the result that these so-called Torula forms constitute physiologically 

 several well-defined sj)ecies, though morphologically they are not to 

 be distinguished from one another. 



Schizomycetes and Schizophyeese.* — In connection with his pre- 

 viously published views on the relationship between the lowest forms 

 of fungi and algge,t W. Zopf describes a Schizophycea to which he 

 gives the name Gliothrix tenerrima, and which appears as a foetid 

 greenish or dusky yellow slime on the surface of water. The filaments 

 are of extreme tenuity, resembling the finest Schizomycetes. It is 

 formed, however, only in the light, and gives the spectrum of chloro- 

 phyll. Its course of development resembles closely certain Schizo- 

 mycetes, as Bacterium cyanogenum, occurring in the three states of 

 zoogloea-colonies, and in the filamentous and spherical forms. Tran- 

 sitions from longer to shorter rods and to cocci occur in the same 

 filament. The cocci might be regarded as belonging to the genus 

 Ajphanocapsa, the rods to the genus Aphanothece. The colonies 

 deliquesce readily in water from the swelling of the jelly. When 

 thus liberated the cocci have a power of spontaneous motion. 



Another interesting illustration of the genetic connection of 

 chroococcaceous forms and filamentous Schizophyceae is furnished by 

 Phragmonema sorcUdum belonging to the Sirosiphoneee, which caused 

 a dirty greyish-blue coating on leaves of Ficus harhata in an orchid- 

 house. In this also chroococcaceous zoogloea-colonies are formed 

 by the cylindrical cells of the filament becoming strongly rounded 



* SB. Bot. Ver. Prov. Brandenburg, 1882, pp. 51-5. 

 t See this Journal, ii. (1882) p. 545. 



