1917] Mitra: Toxic and Antagonistic Effects of Salts on Wine Yeast 81 



The experiments with binary salts were made in the same general 

 way as those with simple salts, but with slight modifications of tech- 

 nique. The flasks were arranged as before in duplicate, but in com- 

 bining the salts in different molecular concentrations the method 

 followed differed from those of previous investigators. 



Of the two salts to be tested for antagonism, one was weighed from 

 the minimum concentration to that of extreme toxicity according to 

 the molecular concentration, and the other was weighed and added 

 to the former in the reverse way in the corresponding flasks. The 

 flasks containing the extreme concentration of each salt did not receive 

 any addition of the other salt. Aside from this, the methods of in- 

 oculation, incubation, and microscopical counting were the same as 

 those described for the single salts. Duplicates were made in all cases 

 and two blanks were used in each series, as checks on the growth of 

 the yeast in the treated flasks. The same yeast, £. dlipsoidcus, no. 66, 

 was employed in these experiments as in the ones with simple salts. 

 The results given are therefore the average of duplicate experi- 

 ments. 



SERIES VI— ANTAGONISM BETWEEN MAGNESIUM CHLORIDE AND 



CALCIUM CHLORIDE 



In this series MgCL and CaCl 2 were combined in various mole- 

 cular concentrations. A series of 16 Erlenmyer flasks was arranged 

 in duplicate with two blank cultures. First, amounts of MgCL cor- 

 responding to from OM to 2.2M were weighed and put in the flasks, 

 as was done with the single salts. The CaCL also was weighed ac- 

 cording to its molecular concentration and put in the same flasks in 

 reverse order, leaving the extreme concentrations of each salt free 

 from the addition of the other. Thus the first two flasks received 

 .72M CaCL without any addition of MgCL, ; the second received .66M 

 CaCL and .001 MgCL ; the third .60M CaCL, and .01M MgCL, and so 

 on to the last couple, which contained only 1.2M MgCL and no addition 

 of CaCL. The remaining flasks were combined in different molecular 

 concentrations, as shown in table 1. Two blanks were taken to which 

 no salt was added. 



In order to facilitate the plotting of the curves, the different 

 combinations of salts have been indicated by letters A, B, C, D, etc. 

 A represents the blank cultures, while the other letters represent the 

 different molecular combinations shown in the table below : 



