The condition is a loss of excitation-power of the nerve of Eckhard, whereby all physiological irritation becomes impossible. This nerve arises from the sacral plexus, any irritation of which, in a healthy state, causes a flow of blood to the corpus cavernosa and spongiosa of the penis; but the constant stimulation of this nerve produces a loss of irritability and paralysis of the parietes of the arterioles of the erectile bodies of the penis, and no relaxation of their valves occurs at any time: a perfect vascular inactivity is the result. These arterioles anastomose with corporal venules which are very tortuous and sacculated and supplied with very large openings and very small outlets compared with the magnitude of their calibres; but the often turgesced condition of these venules causes a dilated condition of the outlets, and any blood that may be conveyed into the corpora through the arterioles will flow out so fast through the dilated venule outlets, that the turgescence necessary to produce erection is impossible. Again, the innate contractility of the trabecular substance must antagonize, to a considerable extent, the erectile tendency of surrounding tissue. Then there is another condition so closely connected with impotence that a mention of it will not be out of place. Impotence consists in a lack of power to effect an erection; but there is a condition, not always impotence, where the person has lost all desire for copulation, and will not make an effort to obtain an erection. He does not attempt to concentrate his will-power, and does not desire any relation whatever with the opposite sex, although he may have been a debauché in his early life. When such a condition has been congenital, there would be reason to suspect deformity or congenital defect. Such person may not be impotent, and if the desire returns it manifests itself in the genitals as soon as the mind is allowed to dwell upon erotic thoughts; and if erection does not occur impotence is present. The loss of semen often subsides in the aged, and atrophy of the testes is not an uncommon result; but some people live to be very old, and are never troubled with senile-impotence.