As Czerny and Keller have stated, it is difficult to define sharply the relation of bone fragility to scurvy. Histologically there is great similarity between the "osteotabes infantum" described by Ziegler and conditions sometimes found in infantile scurvy. The main distinction is that in the latter disorder the lesion is less generally distributed throughout the skeleton, and is particularly marked in a limited area of the bones (epiphyses). In considering this question it should be borne in mind that, experimentally, osteoporosis and scurvy can be brought about by diets which are absolutely dissimilar. For example, Bartenstein showed that young guinea-pigs develop osteoporosis and multiple fractures on a diet of raw milk containing an adequate quota of antiscorbutic vitamine. =Rickets= and infantile scurvy are commonly found associated, although they bear no causal relationship to each other. The distinctive characteristic of rickets is the broad area of osteoid tissue which is formed at the epiphyseal junction, a broad band of incompletely calcified cartilage not found in scurvy. In the latter disease osteoblastic bone growth is greatly inhibited, but what growth does take place occurs in a normal and orderly manner. The osteophytes, for example, which so commonly develop at right angles to the axis of the bone in the subperiosteal hemorrhages, are composed of apparently normal bone. Another marked distinction between the two conditions is the paucity of blood-vessels in the cartilaginous area and in the marrow in scurvy, compared with the increased vascularity so generally encountered in rickets. It is evident, therefore, that although these two nutritional disorders bear a superficial resemblance to each other pathologically, they are radically different and almost antithetical. CHAPTER V EXPERIMENTAL SCURVY There is no mention whatsoever of scurvy in animals previous to 1895, when Theobald Smith wrote: "When guinea-pigs are fed with cereal (it has been observed for some years in this laboratory), with bran and oats mixed, without any grass, clover, or succulent vegetable, such as cabbage, a peculiar disease, chiefly recognizable by subcutaneous extravasations of blood, carries them off in from four to eight weeks." Smith did not pursue the subject further.