296 CHARLES B. LIPMAN 



employed. The kations studied were sodium, potassium, cal- 

 cium, and magnesium. When used alone these chlorides were 

 found to be toxic in the following order: calcium, magnesium, 

 sodium, and potassium. In a variety of combinations of these 

 salts it was found that the toxicity of all of them for B. suhtilis 

 could be very much reduced by mixing any one of them in the 

 same concentrations with a certain other salt even though the 

 latter itself be toxic at that concentration. It was thus found 

 that antagonism existed between sodium and magnesium, be- 

 tween sodium and potassium, and between potassium and cal- 

 cium. Likewise it was found that no antagonism existed be- 

 tween sodium and calcium and none between calcium and 

 •magnesium. 



It was further found in later researches'- that Loeb's concep- 

 tion of the physiologically balanced solution for animals and 

 plants was also valid for bacteria and that sea water which Loeb 

 had looked upon as a natural balanced solution for other organ- 

 isms also proved to be a perfectly balanced solution for B. suh- 

 tilis as obtained in pure cultures from a soil. 



Up to this time, however, but very little attention had been 

 given to the study of the role of the anion in antagonistic salt 

 effects. Loeb in fact as well as Osterhout and other students 

 of this most interesting subject had declared the anion to be of 

 but little significance in antagonistic salt effects and believed the 

 kation to be of greatest importance in that connection. The work 

 of Miss Moore and of Neilson had received therefore but scant 

 attention but is mentioned in Robertson's review^ of the researches 

 carried out on the role of salts in life processes. The writer had 

 believed for some time prior to reading the work above mentioned 

 that antagonism between anions was, a priori, to be expected. 

 Moreover, realizing the fact, when the subject is viewed from the 

 practical standpoint, that the salts occurring in alkali soils are 

 mostly those of sodium combined with hydrochloric, sulphuric, 

 and carbonic acids, it appeared of the greatest practical signifi- 

 cance as well as of scientific interest to determine whether or not 



2 Bot. Gaz., vol. 49, p. 207. 



3 Ergebn. d. Physiol., vol. 5, p. 216. 



