12 



IIARDWICKE'S SCIENCE-GOSSIP. 



A. — Species not producing a mycelium, 



70. ^S". cercvisia:, Meyen. 



Torula cerevisuz, Turpin. 

 Cryptococcus fertiientum, Kiitzing. 

 Cryptococais cerevisicz, Kiitzing. 

 HorDiisciiim cerevisitc, Bail. 

 [Saccharoinyccs ininoi-, Engel ?] 



Cells mostly round or oval, 8-9 /u long, isolated or 

 united in small colonies. Spore-forming cells isolated, 



tions, so that there is an absence of the globular 

 clusters which are so striking a feature in the develop- 

 ment of " high " yeast, when examined at an early 

 stage of growth. " Low " yeast never rises to the 

 surface of the fermenting fluid, which is thus left clear, 

 but it produces, in the opinion of Englishmen at least, 

 an inferior beer. With high yeast, the newly-formed 

 cells rise to the surface as the fermentation proceeds^ 

 and there form large foam-like masses. It is doubtful 

 whether the names "high" and "low" arose from 



Fig. 6. — .?. pastorLinus ; a, the same more highly magnified. 

 (After Pasteur.) 



Fig. 7 — S. ccrevisiiF ; a, a bud-colony ; i, two spore- 

 forming cells. (Aft^r Winter.) 





© 



Fig. 8 — " High yeast," 5". cercziisup ; a, the same, budding 

 actively. (After Pasteur.) 



0^ 



o 



'CO 



Fig. g.— "Low yeast," .S". cerevisice; a, the same, budding 

 actively. (After Pasteur ) 





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//, 



■J-ilA 



s. 



/^/ 



/ 



Ih^ 



u 



/ 



Fig. lo. — Bacillus leprcr ; «, cells from tubercles, 

 fresh; b, a "brown element" coloured with 

 methyl-violet, from a tubercle treated with osniic 

 acid ; c, bacilli, with spores, [a and b, after 

 Hansen ; c, after Neisser.) 



Fig. II. — .S". iitycoderina, budding: a is the 

 Hortniscutn vini of Bonorden. 



11-14 /" long; spores mostly three or four together 

 in each mother-cell, 4-5 yu in diameter. 



In beer, in both high and low fermentation. 



The true beer-ferment is found in the various sorts 

 of beer, in both modes of fermentation ; it is cultivated 

 on a large scale, and then yields the German yeast, a 

 mass which consists of yeast cells and water. 



[There are two races of this species, "high" yeast 

 and "low" yeast. The cells of " low " yeast are 

 slightly smaller, and more oval in shape, than those 

 of " high " yeast, and in budding produce less ramifica- 



these different positions of the yeast, or from the 

 difference in the temperatures at which they work. 

 High yeast ferments at a temperature between 16° C. 

 and 20° C, while low yeast is usually employed at a 

 temperature of from 6° C. to 8° C, antl rarely more 

 than 10° C. In Pasteur's (from a morphological 

 point of view) confused " Etudes sur la Biere,'' these 

 are considered as distinct species, but this position 

 is untenable. 



The wildest possible theories have been started to 

 explain the origin of this ferment. These are of two 



