Gestation

term "large granules." It is of some interest that these granules behave in many ways like the granules of the adrenal medulla which contain the pressor amines. By differential centrifugation it has been shown that the granules with the greatest density contain the largest amount of histamine, and also, that the intravenous injection of a preparation of these granules has less vasodepressor activity than the same quantity of granules after disruption in distilled water. The papers devoted to the release of histamine from its sites in the body list a great variety of substances that have been reported to have the ability to cause this release. Among such substances are: Sensitizing compounds (antigens); compounds damaging to tissues (venoms, toxins); proteolytic enzymes (trypsin); surface-active compounds (Tween 20); large molecules (egg white, Dextran, P.V.P.) ; histamine liberators (dibasic and polybase compounds, Cpd. 48/80); monobasic compounds (alkylamines, antihistamines). The discussions of the origin and fate of histamine in the body are also of considerable interest. Recent work on the excretion of histamine and its alteration products is presented and the fact that in the rat a large portion appears in the urine as imidazoleacetic acid riboside. This book is recommended to all who are interested in histaminephysiologists, pharmacologists, physicians, and medical students. It is clear to the reader that the closing statement of one of the chairmen is validthat there is still a great deal of work to be carried out in this field.