_The Cardio-Vascular System._--The pulse rate is usually rather increased in frequency as compared with that in adult life; extra-systoles are so common in persons who appear otherwise normal that they cannot be regarded as having any important significance. Among Sir George Humphry’s collection of 824 persons over 80 years of age one-fifth had an irregular or intermittent pulse. Although, like arteriosclerosis, a well-marked high blood pressure without evidence of renal disease, to which Sir Clifford Allbutt has given the name of senile plethora or hyperpiesia, is common in the decline of life, it is a pathological and not a physiological change; and a distinction must be drawn between the gradually rising blood pressure seen from birth onwards and an increase above that normal to an arterio-vascular system that has been active for over half a century. In the same way the venous pressure increases with age (Hooker[189]). That a definitely high blood pressure in the aged is pathological appears to be shown by observations quoted by Councilman from the Peter Bent Brigham Hospital, Boston; among 94 patients (male and female) averaging 66 years of age, 44 per cent with cardiac hypertrophy as shown by necropsy, had an average blood pressure of 158 systolic / 88 diastolic, whereas the 56 per cent without cardiac hypertrophy had an average blood pressure of 130/78. In both series the differences between males and females were never more than 7 mm. Hg. From observation of 102 Chelsea pensioners over 75 years of age Thompson and Todd found that the average blood pressure was 145 systolic / 80 diastolic, estimations varying from 190/100 to 115/70, and that the average pulse pressure, or difference between the systolic and diastolic pressures, was 67 mm. They came to the conclusion that it was not possible to arrive at a normal blood pressure for old people on account of the varying conditions of the heart and arteries.[190] The urine, in consequence of the lowered metabolism and general atrophy, is somewhat diminished in quantity with a fall in the solids, though the specific gravity remains about normal. The chlorides are stated to be normal and the phosphates and urea to be diminished. Slight glycosuria as a result of a low sugar tolerance (_vide_ Spence[191]) is not uncommon, especially in obesity. Prolonged confinement to bed has been thought to be responsible for casts in the urine. A trace of albumin is not rare; this may be due to various factors, and in itself is not a cause for anxiety; but a well-marked fall in the specific gravity is a sign of renal inadequacy which may be preceded and anticipated by the discovery of nitrogen retention in the blood. _Sexual activity_ in man wanes generally speaking after 50, but there are great variations in this respect, and sometimes there are periods of considerable excitement in old men, often thought to be associated with prostatic enlargement.