110 PHYSIOLOGY OF YEASTS (Continued) 



Metals and Salts 



Zikes l found that aluminum had a slightly stimulating effect on 

 the fermenting and regenerative function. Bokorny 2 studied the 

 effect of certain uncommon salts. RB 2 SO 4 and Cs 2 SO 4 in the presence 

 of potassium salts favored the development of yeast. Lithium salts 

 proved injurious to yeast propagation An increase of over 0.1 per 

 cent of the potassium phosphates in a medium is not advantageous. 

 Two per cent (NH 4 )2S04 does not seem to hinder the development 

 of yeast. Bokorny, 3 in another paper, has reported a very complete 

 study of the action of metallic salts. Practically all of the metallic 

 salts were studied. Kossowicz 4 has shown that yeasts liberate iodin 

 from KI-mineral-sugar solutions. 



Bokorny 5 has stated that manganese is not poisonous to yeasts 

 if it is in the form of its salts. Budding took place when yeast was 

 put into 1 per cent solution of MnSO 4 , while in a 3 or 5 per cent solu- 

 tion budding was stopped. This is attributed to the fact that, unlike 

 the other metals, manganese does not unite with the protoplasm. 

 Boas 6 studied the effect of arsenic compounds on yeast. He found 

 that, at first, sodium metaarsenite and potassium and sodium arsenate 

 had a repressing action which was eventually overcome if the yeast 

 was kept in contact with these solutions for a period of time. Low 

 temperatures were said to increase the intensity of the poisoning action 

 but without killing the yeast. Mitra 7 found that the chloride of 

 sodium, potassium,, calcium and magnesium are more or less toxic 

 to yeasts in concentrations. KC1 was the least and NaCl the most 

 harmful. 



1 Zikes, H. Influence of aluminum on yeast and beer. Allgem. Zeit. Bier- 

 brau. Malzfabr. 41, 71-4, 83-7. 



2 Bokorny, Th. The influence of cesium, rubidium, and lithium salts on 

 yeast in comparison with the action of potassium and ammonium. Allg. Braw. 

 Hopfen-Ztg. 52, 1469-70. 



3 Bokorny, Th. Action of salts of metals upon yeast and other fungi. Cent. 

 Bakt. Abt. II., 35, 118-197. 



4 Kossowicz, A. and Loew, W. The behavior of bacteria, yeasts and molds 

 towards iodin compounds. Z. Garungsphysiologie, 2, 1913. 



5 Bokorny, Th. The non-poisonous properties of manganese. Chem. Ztg. 

 38, 1290. 



6 Boas, F. Action of arsenic compounds on yeast. Chemical Abstracts, 12 

 (1918), 1101. 



7 Mitra, S. K. Toxic and antagonistic effects of salts on wine yeasts. Calif. 

 Pub. Agr. Sci. (15) 3, 63-102, 1917. 



