SACCHAROMYCES ACIDI LACTICI 265 



sesses small oval or elongated cells. (Fig. 122, A.) The temperature 

 optimum for budding is towards 30 C. Ascs are produced on plas 

 ter blocks at 25 C. in twenty hours, and at 15 C. in forty hours. They 

 are also formed in fermenting solutions and on gelatin. The asco- 

 spores are round or elongated (Fig. 122, B). After a long time, this 







B 



Fig. 122. Saccharomyces fragilis. A, Young Vegetation on 

 Yeast Water with Added Lactose. B, Ascs (after Holm). 



yeast produces a scant scum. At room temperature this yeast forms 

 about 1 per cent of alcohol by volume after eight days and 4 per 

 cent after 4 months. In beer wort, after six days, about 1 per cent 

 of alcohol is formed. According to Bau this yeast ferments lactose, 

 but has no action on melibiose. 



SACCHAROMYCES FLAVA LACTIS. Krueger l 



This species is found in beer to which it contributes an abnormal 

 yellow color, and a disagreeable odor, resembling putrefied urine. It 

 possesses small cells attached in chain formation. They sporulate 

 rapidly on slices of carrot. The^ colonies on gelatin are yellow. Gela- 

 tin is liquefied very rapidly and the colonies cover themselves with a 

 scum. This yeast produces a yellow scum in milk and in a decoc- 

 tion of milk sugar. The coloring matter is formed only in contact 

 with air. 



SACCHAROMYCES ACIDI LACTICI. Grotenfelt 



Grotenfelt 2 has described under this name a yeast which, intro- 

 duced into sterile milk, causes a coagulation and at the same time 

 a formation of acid. Its cells are ellipsoidal (2.0-4.35 ju long and 1.5- 

 2.9 jj, wide). On gelatin, and on agar, it forms white shiny colonies. 

 On potato it forms large moist spots clear gray which turn to a brown. 



1 Krueger, R. Bakter. chemische Untersuchungen kasiger Butter. Cent. 

 Bakt. 7, 1890. 



2 Grotenfelt, G. Ueber die Spaltung von Milchzucker durch Sprosspilze 

 und iiber schwarzen Kase. Fortschr. der Med. 7, 1889. 



