autiful
youths whose love they desired, that they ceased breathing.[109] It may be
added that exactly the same tendency to superficial and arrested
respiration takes place whenever there is any intense mental
concentration, as in severe intellectual work.[110]

The arrest of respiration tends to render the blood venous, and thus aids
in stimulating the vasomotor centers, raising the blood-pressure in the
body generally, and especially in the erectile tissues. High
blood-pressure is one of the most marked features of the state of
detumescence. The heart beats are stronger and quicker, the surface
arteries are more visible, the conjunctivae become red. The precise degree
of blood-pressure attained during coitus has been most accurately
ascertained in the dog. In Bechterew's laboratory in St. Petersburg a
manometer was introduced into the central end of the carotid artery of a
bitch; a male dog was then introduced, and during coitus observations were
made on the blood-pressure at the peripheral and central ends of the
artery. It was found that there was a great general elevation of
blood-pressure, intense hyperaemia of the brain, rapid alternations, during
the act, of vasoconstriction and vasodilatation of the brain, with
increase and diminution of the general arterial tension in relation with
the various phases of the act, the greatest cerebral vasodilatation and
hyperaemia coinciding with the moment following the intromission of the
penis; the end of the act is followed by a considerable fall in the
blood-pressure.[111] I am not acquainted with any precise observations on
the blood-pressure in human subjects during detumescence, and there are
obvious difficulties in the way of such observations. It is probable,
however, that the conditions found would be substantially the same. This
is indicated, so far as the very marked increase of blood-pressure is
concerned, by some observations made by Vaschide and Vurpas with the
sphygmanometer on a lady under the influence of sexual excitement. In this
case there was a relationship of sympathy and friendly tenderness between
the experimenter and the subject, Madame X, aged 25. Experimenter and
subject talked sympathetically, and finally, we are told, while the latter
still had her hands in the sphygmanometer, the former almost made a
declaration of love. Madame X was greatly impressed, and afterward
admitted that her emotions had been genuine and strong. The
blood-pressure, which