Comparative Studies on Respiration. Xv. the Effect of Bile Salts and of Saponin upon Respiration

I t was pointed out by Osterhout I 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 NaC1 (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 taurocholate acts like CaCI~ in decreasing conductivity and in antagonizing NaC1. Whether this similarity would be found if other criteria were used remained an open question. The experiments of the writer 3 showed that, when respiration is employed as a criterion, CaCI~ antagonized NaC1. Similar results were obtained by Gustafson. 4 In view of this it became especially interesting 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 subtills and the technique was similar to that described in previous papers3 The results are shown in the figures. F i g . 1 shows the effects of sodium taurocholate (0.0000125, 0.000015, 0.001,0.0025, and 0.01 M) upon the rate of respiration (expressed as per cent of the normal rate). This organic salt is similar in its