1917] Mitra: Toxic and Antagonistic Effects of Salts on Wine Yeasi 99 



Summary 



PAET A— TOXIC EFFECTS OF SINGLE SALTS 



1. Each of the four single salts— KC1, MgCL, CaCL, and Nad- 

 is more or less toxic to the yeast, Saccharomyces ellipsoideus, at certain 

 concentration. KC1 is the least toxic and NaCl the most for the yeast 

 (no. 66) used. 



2. The lower concentrations of each salt stimulate the growth of 

 yeast. The highest number of yeast cells in microscopical count was 

 found at .2M KC1, .1M MgCL, .01 M CaCL, and .001M NaCl, KC1 

 being the most favorable and NaCl the least. Beyond the favorable 

 concentrations the various salts are toxic to yeast. 



3. The concentrations of salts that inhibited the growth of yeast 

 cells were found at 2.2M KC1, 1.2M MgCL, .7M CaCL, and .2M NaCl. 



4. The results of the experiments are quite different from those 

 found with either bacteria, the higher plants or animals. The yeast 

 stands in this respect midway between plants and animals and swings 

 to either direction according to the environment. 



5. The salts used had a marked effect on the size and appearance 

 of the yeast. Taking decrease in size as a criterion, the salts affected 

 the yeast toxically in the same relative ways as indicated by the rate 

 of multiplication of the cells. 



PAET B— ANTAGONISTIC EFFECTS OF COMBINATIONS OF SALTS 



1. As shown by growth of yeast, the variation in antagonism be- 

 tween the four single salts in all possible combinations may be ar- 

 ranged in order as follows: 



1. MgCL vs. CaCL (most i 



2. KC1 vs. CaCL 



3. MgCL vs. NaCl 



4. KClvs. NaCl 



5. KC1 vs. MgCL 



6. CaCL vs. NaCl (least) 



2. The effect of binary salts with yeast, whether positively or nega- 

 tively antagonistic in comparison to animals, plants and soil bacteria, 

 may be tabulated as follows: 



