In view of the obvious advantages of an injectable antipernicious anemia substance and the promising results reported by Gansslen, 1 Selander, 2 van Leeuwen, 3 Strauss, Taylor and Castle 4 and others with intravenous and intramuscular materials, this work was undertaken with the twofold objective of producing an improved injectable material that would be ( a ) of a definitely standardized potency and ( b ) of a chemical refinement sufficiently great to remove the irritating and objectionable elements and thus permit safer, more convenient and painless subcutaneous use. In order to begin with material of highest known potency, we used equine liver prepared as reported in our previous work. 5 This method was essentially similar to that of Strauss, Taylor and Castle. 4 Absolute alcohol sufficient to bring the liquid up to 95 per cent was added to the liver extract. After standing, the precipitate was separated and dissolved in a convenient amount of water, and a