1917] Mitra: Toxic and Antagonistic Effects of Salts on Wine Yeast 75 



NaCl shows a directly opposite reaction with yeast from that 

 found by Lipman 11 with soil bacteria. Both Loeb and Ostwald found 

 NaCl to be toxic for animals, but less so than we have found with 

 yeast. The toxicity of NaCl to animals may be compared with the 

 toxicity of NaCl., to yeast. Loeb 3 found it impossible to develop 

 embryos in the egg of Fundulus at .625MNaCl. Osterhout 8 ' 9 found 

 that a .375M solution of sodium chloride is fairly toxic to marine 

 plants. Young plants of a fresh-water alga, Vaucheria scssilis, could 

 not live at a .094M concentration of sodium chloride, and even a 

 concentration of .0001M NaCl was found to be toxic. Magowan has 

 shown that sodium chloride is very toxic to wheat seedlings and down 

 to .0211 the root hairs did not grow at all. The relation of yeast to 

 plants is thus to a certain extent shown by similar physiological 

 behavior. 



It may be noted here that the experiments with yeasts have been 

 conducted on the same general principle followed by previous investi- 

 gators with animals, plants, and bacteria. The number of yeast cells 

 was taken as the measure of multiplication or activity and was de- 

 termined by a microscopical count of each flask every forty-eight 

 hours. It must be admitted that experimental errors may occur in 

 counting, but as the numbers were taken from the average results of 

 two sets of duplicates it does not interfere with the validity of the 

 final result, as the range of variation between the results of these two 

 sets of duplicates was only between and 10 per cent calculated from 

 the mean variation. 



SERIES Y— EFFECT OF THE TOXICITY OF SALTS ON THE 

 MICROSCOPICAL APPEARA^X , E OF YEAST CELLS 



It is generally known that all salts at certain concentrations are 

 more or less toxic to living organisms. Yeast shows its physiological 

 condition in relation to various salts in characteristic ways. It is 

 evident from the above experiments that in this respect it occupies 

 a place between the animal and the plant kingdoms. Although yeasl 

 grows normally in a physiologically balanced solution, for which 

 grape juice answers in every way, the addition of a small amount of 

 a favorable salt, as potassium chloride, may stimulate the growth a 

 great deal. This is of some practical zalue to zymologists. 



Yeast is affected very remarkably by the toxicity of salts at dif- 

 ferent concentrations. In the extreme concentrations it apparently 



