COMPARATIVE STUDIES ON RESPIRATION. 

 XV. The Effect of Bile Salts and of Saponin upon Respiration. 



By matilda MOLDENHAUER BROOKS. 

 (From the Laboratory of Plant Physiology, Harvard University, Cambridge.) 



(Received for publication, January 15, 1921.) 



It was pointed out by Osterhout^ that substances which increase 

 the electrical conductivity of tissues are antagonized by those which 

 decrease it. An illustration of this is seen in antagonism between 

 NaCl (which increases conductivity) and Na taurocholate^ (which 

 decreases it). This case has additional interest as an example of 

 antagonism between anions as well as of antagonism between organic 

 and inorganic substances. 



The experiments on electrical conductivity indicated that Na tauro- 

 cholate acts like CaCl2 in decreasing conductivity and in antagonizing 

 NaCl. Whether this similarity would be found if other criteria were 

 used remained an open question. 



The experiments of the writer^ showed that, when respiration is 

 employed as a criterion, CaCl2 antagonized NaCl. Similar results 

 were obtained by Gustafson.^ In view of this it became especially in- 

 teresting to study the behavior of tissues under the influence of Na 

 taurocholate. 



In the experiments which were made for this purpose the organism 

 studied was Bacillus subtilis and the technique was similar to that 

 described in previous papers.^ The results are shown in the figures. 



Fig. 1 shows the effects of sodium taurocholate (0.0000125, 

 0.000015, 0.001,0.0025, andO.Ol m) upon the rate of respiration (express- 

 ed as per cent of the normal rate) . This organic salt is similar in its 



1 Osterhout, W. J. V., Science, 1915, xli, 255. 



2 Osterhout, W. J. V., /. Gen. Physiol., 1918-19, i, 405. 



3 Brooks, M. M., /. Gen. Physiol., 1919-20, ii, 5. 



* Gustafson, F. G., /. Gen. Physiol., 1919-20, ii, 17. 

 5 Brooks, M. M., /. Gen. Physiol., 1919-20, ii, 5, 331. 



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