BEER-SEED. 



167 



No bacteria were obtained on these plates. This yeast fermented grape-sugar in peptone 

 water readily and also cane-sugar and maltose, but not lactose. 



This yeast grew on potato in a thick whitish layer. It grew readily in the thermostat 



tem 



,,-,. . 



."s 



* life 



. -^ - . ">' v "" -" ::.''' "''-' - - ' "' :"-''' 



Fig. 46.* 



1 



m 





V 



ijt*9fr 



MC ' 



Fig 47-t 



i ftoosat 



Fig. 48. % 



at 28 C. On agar streaks it sporulated freely after some days, the protoplasm, rounding off 

 into two or more parts. Often three spore bodies and sometimes four or more in a cell were 

 observed (fig. 49). The appearance and behavior of this yeast sug- 

 gested Saccharomyces cerevisiae. 



Sterile litmus milk inoculated by putting some of the grains into it 

 did not redden, did not coagulate at once and did not produce any gas- 

 bubbles. Gradually the litmus was reduced and remained reduced for 

 a very long time. The milk also finally curdled. It was blue after the 

 reduction ceased. 



It would appear, therefore, that some kefir-like grains contain a 

 yeast incapable of fermenting lactose, while grains from other sources 

 contain a yeast capable of fermenting lactose. The relation of kefir to the ginger-beer 

 fermentation remains to be determined. 



Fig. 49. 



*Fig. 46. Free-hand unstained section through one of the "beer-seeds," surface of grain being at left. The 

 uniform gray structure represents bacterial zoogloea?, the darker masses the undisturbed position of imprisoned clumps 

 of yeast. 



fFic. 47. A small portion of "beer-seed" crushed in water and drawn after staining with carbol fuchsin. The 

 yeasts buried in the zoogloeae were not budding, most of them were globose or nearly so. 



tFic. 48. Another crushed-out water mount of "beer-seed," showing both round and elongate yeasts, the con- 

 tents omitted, x and y stained alike with fuchsin and both forms were full of coarse granules. 



Fig. 49. Spores or spore-like bodies in yeasts on agar sub-culture (streak) made from an agar-plate poured from 

 crushed "beer-seed." Age 16 days. Stain, carbol fuchsin. 



