artificial sexual excitations that civilization brings with it.

=Sexual Power.=--The individual variations in the sexual instinct are
enormous, and may be said to vary from zero to an intense and
perpetual excitation called _Satyriasis_. By sexual power is
understood the faculty of accomplishing coitus. This power in the
first place requires strong and complete erections, as well as the
faculty of following them by frequent seminal ejaculations, without
being precipitate. Impotence or incapacity for coitus belongs to
pathology and consists usually in the absence or defectiveness of
erections. Sexual power and appetite generally go together, but not
always, for it is possible to be powerful with feeble sexual appetite,
and intense appetite sometimes goes with impotence; the latter
condition, it is true, is pathological. Sexual power also varies so
much in individuals that it is hardly possible to fix a limit between
the normal and the pathological.

The sexual power and appetite in man are strongest on the average
between 20 and 40 years, especially between 25 and 35. But, while
young men of 18 to 20 years or more may be still tranquil, without
having had seminal ejaculations, one often finds, among races who
mature earlier, boys of 12 or 16 who are fully developed both in
sexual power and appetite. In our Aryan races, however, when this
occurs before the age of 14, it is a case of pathological precocity.
The late appearance of sexual power and appetite is rather a sign of
strength and health.

After the age of 40, the sexual power slowly diminishes, and after the
seventieth year, or even before this, becomes extinct. Exceptionally
one finds old men of 80 who are still capable. Normally the sexual
appetite diminishes with age; often, however, especially when it is
artificially excited, it lasts longer than sexual power.

As regards sexual power we must distinguish between that of copulation
and that of fecundation. The power may exist without the latter, when
the testicles have ceased to functionate, while the other glands, in
particular the prostate, second the venereal orgasm by their
secretion, when the power of erection is still preserved. Inversely,
the testicles may contain healthy spermatozoa in the impotent. In this
case artificial fecundation by the syringe is practicable.

=Individual Variations in Sexual Power.=--The fact that there are men
who for several years can copulate several times a day proves t