Histological observations were carried on the skin at the root of the left third finger in 25 cases mainly composed of advanced age. Also the investigations were conducted on the relationship between the biopsy picture of the spleen in 7 cases of advanced age accompanied by hypertension as well as the renal function on one hand and the capillary blood vessel picture at the root of finger nail; and the following results were obtained. 1. It seems that factor such as thick keratincus layer, deep melanin pigment, the paucity of capillary vessels and changes in the adjacent connective tissue are responsible for making it impossible to reveal the capillary blood vessel picture at the root of finger nail. 2. The tissue picture and the capillary blood vessel picture show mo phologically a rather parallel relationship but the blood circulation, being quite a complex problem, does not reveal any distinct relationship with these pictures. 3. From the standpoint of age, the keratinous layer grows thicker, the melanin pigment deeper, changes of connective tissue greater, and the number of capillary blood vessels lesser with advance in age. Likewise the wall of capillary arteries grows sclerotic and the partition ing of lumen is less marked along with advance in age. 4. In those showing sclerosis of the arteries in the radius n y reveal the changes mentioned above. 5. As for the relationship with the blood pressure, although arterial sclerotic changes can be recognized in hypertension, no marked changes can be observed in the cases of hypertension due to renal diseases. 6. The degree of arterial sclerosis and the disturbances of renal function in the biopsy of the kidney have about a parallel relation, and in those showing a more marked disturbance also more marked changes can be observed in their capillary blood vessel picture.