This section is from the book "The Transmission Of Life. Counsels On The Nature And Hygiene Of The Masculine Function", by George H. Napheys. Also available from Amazon: The Transmission of Life.
From what has been said, the reader will now be prepared to understand the essential difference which exists between a nervous function, like that concerned in the reproduction of life, and muscular power. This antagonism in their nature exists: by frequent exercise the muscular system increases in strength, and decreases in irritability; but the nerve force, by repeated calls upon it, increases in irritability, but decreases in strength. The more frequently sensation is evoked in a nerve, the greater is its sensitiveness and its debility. This physiological law, first distinctly enunciated by a celebrated French anatomist, is constantly overlooked. From it we learn that in order to preserve in the greatest vigor and most perfect health any nervous function, our aim should be to excite and stimulate it as little as possible. Nowhere does this law find a more striking illustration than in those functions which pertain to sex. And the secret, therefore, of preserving their activity to advanced years, resolves itself into avoiding all stimulants and excitants. By this we do not mean either to recommend asceticism, or uniform continence, but to observe temperance and discretion, to limit one's self in the use of those articles of food or drink which by stimulation ultimately debilitate, and to govern one's life by sound laws of health and morals. It is in this sense we shall proceed to speak of a sedative yet fortifying nourishment, as