228 THE ORGANISMS IN YEAST. 



in worts and beers, and which has recently been investigated at 

 length by C. Hansen, of the Carlsberg Laboratory ; and certain 

 Bacterial forms (No. lo), which, by their power of inducing a 

 gelatinous formation, sometimes cause much injury in manufactur- 

 ing operations. These species are, however, rarely met with in 

 ordinary yeast; at any rate, in this country. They are more com- 

 monly to be found in worts, or in beers themselves, than in the 

 yeast which is used to start the fermentation. 



EXPLANATION OF PLATE XXV. 



Fig. 1. — Saccharomyces from the yeast of a Burton Brewery. 



,, 2. — Ditto from a West of England Brewery, where artificial sac- 

 charine is used. 



,, 3. — Ditto from a Northern Brewery, showing round or spherical 

 cells. (1-lOth in. obj., 3 oc.) 



,, 4. ^ Cells of Saccharomyces in different stages of development, 

 , , 5. > in the fermentation of a brewer's wort ; taken at intervals of 

 ,, 6, J 48 hours. (]-10th in. obj., 3 oc.) 



,, 7. — Acetic ferments employed in vinegar making. 1-lOth in. 

 obj., 3 oc. 



,, 8. — Cells of B. lactis, shewing increase by sub-division, 1-lOth 

 obj., 3 oc. 



,, 9. — Cells of Bacillus subtilis, from a brewer's wort when putrid, 

 1 -10th obj., 3 oc. 



,, 10. — Bacteria inducing a ropy or gelatinous change, 1-lOth obj., 

 3 oc. 



,, 11. — Mycoderma cerevisise, as found in stale beer or malt 

 infusion, 1-lOth obj., 3 oc. 



,, 12. — Saccharomyces apiculatus from a peculiar acid beer, 1-lOth 

 obj., 3 oc. 



