68 University of California Publications in Agricultural Sciences [Vol. 3 



and the check flasks controlled any slight variation it may have 

 caused. 



Salts Used. — During February, 1916, a series of experiments in 

 two parts was planned. The first concerned the toxicity of the single 

 salts and the second the antagonistic effects of all their binary and 

 ternary combinations, as follows: 



I. Toxicity of the Single Salts 



1. KC1 3. CaCL 



2. MgCL 4. NaCl 



II. Antagonistic Effects of Combinations 

 A. Binary Combinations 



1. MgCL + CaCL 4. KC1 + NaCl 



2. KC1 + CaCL 5. KC1 + MgCL 



3. MgCL + NaCl 6. CaCL + NaCl 



B. Ternary Combinations 



1. NaCl + KC1 + CaCL 3. NaCl + MgCL + CaCL 



2. NaCl + KC1 + MgCL 4. KC1 + CaCL + MgCL 



A. Experiments "With Single Salts — Toxic Effects 



In all cases chemically pure salts (Baker's analyzed) were used. 

 Each amount of the single salts was carefully weighed and put into 

 the flasks, except .001M and .01M, which were added as solutions of 

 known strength according to molecular weights. The following pro- 

 portions were taken : 



1. KC1 — .001M to 2.2M* Molecular 



2. MgCL — .001M to 1.2M 



3. CaCL — .001M to .7M 



4. NaCl — .001M to .2M 



All of these solutions were clear except the calcium chloride, which 

 gave an appreciable amount of coagulated precipitate of calcium phos- 

 phate with the phosphorus of the synthetic solution. This, however, 

 did not interfere with the experiment, as the precipitate disappeared 

 with the growth of the yeast and the solution finally became almost 

 clear. The tables and curves given in each case show the grow T th of 

 yeast at every forty-eight hours in the different molecular concen- 



i M represents the degree of concentration in a solution which contains one 

 gram molecule of the substance in one litre of solution. 



