2. PHYSIOLOGY.
In the treatment of the physiology of the various structures just described, we may well reverse the order of treatment, thus leading up step by step to a consideration of the more important organs.
a. Urethra. The canal or duct of the penis is called the urethra, and it is important in considering its physiology to remember that it has not only a double function to perform, but that the performance of one function in a measure temporarily unfits it for performance of the other and makes it necessary for a special measure of preparation.
The urinary excretion from the kidneys collecting in the urinary bladder is passed out periodically through the urethra. This same channel must transmit periodically secretions from the sexual apparatus.
b. Cowper's Glands secrete only under sexual excitement, and usually they secrete only when the sexual excitement reaches a stage which induces an erection. The secretion is composed of a clear alkaline mucus.
The purpose served in the natural economy by this alkaline mucus is a very important one and it is essential that every young man should understand it.
It will be remembered that the male urethra affords passage not only for the urine, but also for the generative products. The urine is acid in reaction and the frequent passage of urine along the urethra leaves that duct acid in reaction under usual conditions. The spermatozoa are very sensitive to acid and their vitality is seriously impaired by acid of any kind, particularly the acid of the urine. Nature has provided that the secretion from Cowper's glands should precede the generative products along the urethra, thus neutralizing the acid and insuring for the spermatozoa an alkaline passage from the body.
Besides this important function of the secretion from Cowper's glands, the slimy transparent mucus appearing at the glans penis under sexual excitement serves as a natural lubricant covering the glans of the male organ. A secretion from the female similarly prepares her organs for sexual contact so that the delicate mucous membrane, particularly of the female organs, shall not suffer abrasion.
Many young men have experienced the appearance of the secretion from Cowper's glands and wholly misunderstanding its nature have feared that they were losing some vital fluid. This misunderstanding of the nature of this fluid makes the young man especially subject to the misrepresentations of the advertising quack and charlatan who allege that he is losing vital fluid and will, if not treated, undergo general debility and loss of procreative power. This brief explanation of the significance of the secretion of Cowper's glands will protect the young man from any such misrepresentations.