1917] Mitra: Toxic and Antagonistic Effects of Salts on Wine Yeast 65 



general, however, the results with all three classes were of the same 

 kind; that is, single salts, hitherto considered non-toxic, were found 

 to be toxic to organisms, while various combinations of these salts 

 showed antagonism or reduction of toxicity in the presence of each 

 other. In accordance with these facts, a physiologically balanced 

 solution can be made by using proper concentrations and proportions 

 of the various salts found in the solutions to which the organism is 

 accustomed. 



So far as the writer could ascertain, no one has investigated the 

 behavior of yeast in this respect. Results of investigations of the 

 effects of the heavy metallic salts, such as mercuric chloride, silver 

 nitrate, etc., on yeast have been published (Bokarny 12 ), but nothing 

 has appeared upon the toxic and antagonistic effects of such salts as 

 sodium chloride, potassium chloride, calcium chloride, and magnesium 

 chloride. This field therefore seemed especially inviting, and it was 

 with the idea of studying the fundamental relations existing between 

 yeast and the chlorides that the writer undertook the work summarized 

 in the following pages. 



Acknowledgments 



The experiments on which this paper is based were carried out 

 under the general supervision of Professor W. V. Cruess, and I am 

 indebted to Professor F. T. Bioletti for suggestions and critical read- 

 ing of the manuscript. 



Method of Experimentation 



In the selection of a yeast for my investigation I was led to use 

 the wine yeast, Sacckaromyces ellipsoid eus, by the fact that it is one 

 of the most useful of all yeasts and is universally used in wine making. 

 It is also one of the most vigorous, is easy to grow, and gives definite 

 results in a few days. 



The particular yeast, no. 66, used in this experiment, was isolated 

 by William V. Cruess from one of the wineries in northern California. 

 It has been found by repeated trials that specimens of Sacckaromyces 

 ellipsoidcus collected from different sources are not identical as to 

 their physiological characters in every respect, and so do not respond 

 in different salt solutions in the same way. An experiment showing 

 this will be described later. 



Although work on this line may not have immediate practical 



