THE TESTICLES AND THEIR FUNCTION.

Then let us proceed at once to a study of these organs of reproduction. For the present it will be sufficient for you to understand about the testicles and penis. The testicles are the two bodies somewhat like flattened balls that are suspended between the upper part of the thighs. They are called glands. A gland is an organ that manufactures something from the blood. The liver is the largest gland in the body. It manufactures bile from the blood. The salivary glands manufacture saliva from

One of the Testicles with part of its enveloping membranes removed, showing it as it appears during life suspended in the scrotum.

the blood.

The saliva moistens the food in the
But what the testicles

mouth and aids digestion.

manufacture, is in many respects more wonderful than either of these. It is called semen or the seed

of man.

When we examine the testicles we find large arteries that carry pure blood to them to be used in manufacturing semen, and large veins that carry the impure blood away. Wise men have observed that when an organ is supplied with large blood vessels it is an important organ. And the large and numerous blood vessels of the testicles testify to their importance.

HOW SEMEN IS MANUFACTURED.

But how do they manufacture the semen? This is not quite so easy to explain, and it may be sufficient for you to know that they do.

But there are

When the test

some things that we can tell you. icle is cut in two, numerous little, indistinct white lines are observed intermingled with the general pink color of the rest of the gland. If you ever have an opportunity to examine the testicles of the lower animals you can see these. (The butcher might supply you with them.) When these white lines are carefully examined under a microscope they are found to be little tubes and they are so numerous, that if

they should be dissected out and placed end to end, they would reach a long distance. It is these little tubes that take from the blood the necessary substance and manufacture the semen.

The Testicle cut in two, showing its internal structure and the litt tubes that carry the semen to the Vesiculae Seminales together with part of its blood vessels.

These little tubes join together and form larger tubes much like brooks and creeks unite to form rivers. The larger ones leave the testicles and continue to unite with each other, and the very largest

ones extend upward to the base of the bladder where they unite with little vessels.

WHERE THE SEMEN IS STORED.

The semen is conveyed through the tubes to these little vessels on the base of the bladder-the vesiculae seminales-where it is stored and remains

The Bladder, base view, showing the seminal vessels on each side, the beginning of the urethra which carries the urine from the

bladder and the prostate gland at the neck of the bladder.

until it is needed, or else is lost by an abuse of these organs, as will be explained later.

The bladder and penis laid open. This shows the connection between bladder and penis, and the urethra extending through the neck of the bladder and the entire length of the penis. The corpus cavenosum on either side of the urethra is the sponge-like part that is filled and distended with blood during erection.

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