In the field of nutrition there have been evolved methods for the determination of deficiencies of the various vitamins in the diet. These methods, now definitely established, apply to both manifest and latent avitaminosis. The search is still continuing for finer methods which will detect the earliest manifestations— even before clinical signs become evident. In this connection there have recently appeared a number of papers concerning the antiscorbutic vitamin C.
Hess1 in 1914 demonstrated, by means of the blood pressure tourniquet, the increased fragility of the blood capillaries in manifest scurvy as evidenced by the development of petechial spots along the forearm. He found that the test was positive in the majority of cases of this disease, indicating a weakness of the capillary vessel walls due to a failure on the part of the endothelial cells to form cement substance. In 1928 Öhnell,2 too, established the value of