244
CAUSE OP ERECTION.
sum, by means of galvanism, in a livings horse. Hence they would
seem not to be muscular.*
The principal exciting cause of the erection of the penis is, as is
well known, nervous irritation, originating in the part itself or derived
from the brain and spinal marrow. Congestion of the brain and
spinal cord has the same effect, and it is from this cause that the
above-mentioned phenomena are sometimes produced in persons
hanged. The nervous influence is communicated to the penis by the
pudic nerves which ramify in its vascular tissue. Guenther has
observed that, after division of these nerves in the horse, the penis is
no longer capable of erection.t The stallion on which the experi¬
ment was performed was led to a mare; he showed desire to cover,
but no erection of the penis took place. On the following day the
penis was swollen, but not in a state of erection. More recently
Guentherf; has repeated this experiment, and with a similar result as
to the effect on the penis; but the horse did not, as in the former in¬
stance, show any sexual desire when led to a mare after the opera¬
tion.
My discovery of the remarkable structure of the arteries of the
corpora cavernosa penis throws new light on the phenomena of
erection. The arteries of the corpora cavernosa have two sets of
branches. When the arteria corporis cavernosi is injected with
size and vermilion, the injected matter always fills the venous cells;
and if it is afterwards washed from them, the arteriæ helicinæ will
be seen injected.§ They come off from the side of the arteries, and
consist of short tendril-like branches, terminating abruptly by a
rounded, apparently closed, extremity, turned back somewhat on
itself. The means by which during life they are enabled to force
blood into the cells, must be an increased attraction excited between
their coats and the blood by the nervous influence transmitted to
them from the spinal cord, in consequence of which an increased
quantity of blood flows to them. This discovery throws new light,
at the same time, upon the mutual action of the blood and smaller
vessels in other parts, and upon the phenomenon of active turges¬
cence, or turgor vitalis. [| The blood is returned from the corpora
cavernosa partly by small veins, running at the sides and on the sur¬
face of these bodies into the vena dorsalis, partly by deeper veins
which issue from the corpora cavernosa at their root, and enter im¬
mediately the venous plexus, situated behind the symphisis pubis.
The fact, then, that the vena dorsalis does not return the blood from
* Müller’s Archiv. 1834, p. 50; 1835, p. 26.
f Meckel’s Archiv. 1828, p. 364.
X Untersuch und Erfahr, im Gebiete der Anat. Physiol, und Thier-arzneikunde.
Abstracts are given in Müller’s Archiv. 1838, p. clxiii. and in Valentin’s Reperto¬
rium, 1838.
§ Prof. Valentin (Müller’s Archiv. 1838. p. 182) denies the existence of the
arteriæ helicinæ; he supposes erection to be in a great measure due to the active
dilatation of the veins by muscular fibres, attached to tendinous tissue between the
anastomosing veins; but the characters on which he founds his belief that the fibres
in question are muscular, are not conclusive.
J) Müller’s Archiv. 1834, p. 202, tab. xiii.