Biological role of magnesium.

HE BIOLOGICAL n#{248}ui of magnesium is of considerable importance in the processes of synthesis in the organic world. According to the work of Academician V. I. Vernadskii, chlorophyll contains up to 0.2 per cent magnesium. Magnesium enters into the composition of proteins, of plasma, and of the basic colloids of the living body. The magnesium in living matter constitutes n.10_2 of its weight. It is known that chiorophylls a and b and bacteriochlorophylls contain magnesium coordinately linked with the nitrogen of pyrrole nuclei, in the same way as iron in hemoglobin and cytochrome. Magnesium is of great importance in the processes of photosynthesis by chlorophyll. According to Willstaetter and Stoll (1913), the part that magnesium plays in the structure of chlorophyll and particularly its complexes raises the question of its role in assimilation processes. In achlorophyllic plants magnesium also takes a promi-