1917] Mitra: Toxic and Antagonistic Effects of Salts on Wine Yeast 69 



trations of each salt as indicated above. In the microscopical count 

 one million yeast cells per cubic centimeter was taken as an appreci- 

 able number; below that it was not considered that any appreciable 

 growth had taken place. 



SERIES I— POTASSIUM CHLORIDE 



Thirty 200 c.c. Erlenmyer flasks were arranged in duplicate, in- 

 cluding two blanks. The first pair had no salt added and was used 

 as a check. The second pair had .001M KC1 and the third .01M KC1, 

 and so on to the last pair, which had 2.2M KCL as shown in the table 

 below. Then, with a 100 c.c. pipette one hundred cubic centimeters 

 of the diluted synthetic solution (5°Bal.) were put into each flask. 

 The flasks were plugged with cotton, sterilized, and inoculated with 

 yeast, as stated before, and put into the incubator, and counted every 

 forty-eight hours. The results are shown in table 1 and the curves 

 in figure 1. 



The curves have been plotted from the results of every forty-eight 

 hours' growth, taking the various concentrations of potassium chloride 

 as abscissae and the number of yeast cells, counted in millions, as 

 ordinates (fig. 1). Following the table and the curves, it is evident 

 at a glance that potassium chloride up to the concentration of .2M 

 accelerates the multiplication of the yeast. Beyond this it becomes 

 gradually more and more toxic until at 2.2M the yeast cells entirely 

 cease to multiply. Both Magowan 10 and Lipman, 11 especially the 

 former, found a strong resemblance between potassium chloride and 

 sodium chloride in their action on wheat and on Bacillus subtilis. 

 The yeast shows physiological characteristics differing from those of 

 either the bacteria or the wheat. 



Lipman 11 found sodium chloride the least toxic to Bacillus subtilis 

 and potassium chloride second. Magowan, 10 with wheat, found this 

 position reversed, the potassium chloride being less toxic. Both ob- 

 servers found that these salts were very similar in their degree of 

 toxicity. To yeast sodium chloride is the most toxic of the four salts 

 and potassium chloride the least. Ostwald 4 in experimenting with 

 animals {Grammarus) found potassium chloride the most toxic, and 

 Loeb's work 2 - 3 with Fundulus corroborates this to a certain extent. 

 The reaction of yeast, therefore, differs from that of bacteria of the 

 higher plants or of animals. 



