The silver nitrate staining reaction for ascorbic acid in the adrenal, pituitary and ovary of various species of animals.

SZENT-GY6RYGI [1928] has demonstrated that when a section of the adrenal of the ox is immersed in 0 4 % AgNO3 solution, its cortex darkens owing to the deposition of metallic silver. The reduction, he concluded, was due to the presence of ascorbic acid (hexuronic acid). In view of the recent observations on the high and persistent antiscorbutic activity of ascorbic acid it became obvious that the above observation could be utilised in studying the function of ascorbic acid in the development of scurvy. The experiments to be described here were originally undertaken by Zilva with the hope of obtaining information concerning the problem of the identity of ascorbic acid with vitamin C. In this respect suggestive but not conclusive evidence has so far been obtained from this investigation, but some facts have emerged which we consider of sufficient interest to be put on record. In preliminary experiments guinea-pigs on a scorbutic diet receiving various doses of decitrated lemon juice and others subsisting on a diet containing cabbage ad lib. were examined. It transpired that although the cortex of the adrenals from the animals receiving cabbage ad lib. darkened markedly on immersion in the AgNO3, this was not so in the case of the adrenal glands from animals which were receiving daily doses of as much as 10 cc. of decitrated lemon juice, although the guinea-pigs were found at the post mortem examination to be in excellent condition and free from scurvy. Even the microscopical examination of sections of the glands treated with AgNO3 did not reveal any deposition ofAg in the adrenal cortex of the guinea-pigs protected with high doses of decitrated lemon juice. Yet histological sections of the adrenals from these animals did not show any abnormality. The search when extended to other organs from various species of animals, irrespective of their susceptibility to scurvy, revealed that certain other organs showed the AgNO3 staining reaction macroscopically, especially the anterior and intermediate lobes of the pituitary gland, which in some species reduced the reagent even more markedly than the cortex of the adrenal. The disparity in the intensity of staining in these two glands was particularly marked in the human subject, where with very few exceptions the anterior lobe of the pituitary