The recognized causes of interruption of the circulation and infarction of the viscera are embolism, thrombosis, arteriosclerosis and obliterative endarteritis. In case of gangrene of the extremities neurogenic vascular spasm (Raynaud's disease) and ergot intoxication must be added to this list. In view of the relative frequency of these circulatory disturbances in adults, it is surprising that similar lesions of bones have not been more frequently reported to accompany them. As was brought out under general considerations in part I of this study, most of the lesions resulting from nontraumatic interruption of circulation of bone in adults that have heretofore been described have not definitely been traced to the aforementioned causes and with some of the lesions to be described here there is much uncertainty either as to the cause or as to the exact mechanism of action of the exciting factor. That arteriosclerosis, obliterative endarteritis and neurogenic and toxic