COMPARATIVE STUDIES ON RESPIRATION. X. Toxic AND ANTAGONISTIC EFFECTS OF MAGNESIUM IN RELATION TO THE RESPIRATION OF BACILLUS SUBTILIS

The behavior of magnesium is of special interest since in studies on antagonism magnesium has been found to occupy an intermediate position between the monovalent and the bivalent metals. In many cases it can act as an antagonist to calcium as well as to sodium. As no investigations on respiration have been undertaken from this point of view, the writer has made some experiments on this subject. The experiments of Lipman 1 on the rate of ammonificafion of Bacillus subtilis have shown that there is some antagonism between sodium and magnesium. On the other hand he found no antagonism, but increased toxicity, when magnesium and calcium were combined3 Kelley, ~ in studying the ammonification and nitrification of certain soils, found no antagonism between magnesium and sodium. This sort of antagonism was observed, however, in the case of nitrogen fixation by Azotobacter chroococcum, as reported by Lipman and Burgess2 In view of these facts it seemed desirable to study the effects of magnesium upon the respiration of Bacillus subtilis. The technique employed was the same as that described in a previous publication. 5