The picture of muscular irradiation presented under these circumstances differs but slightly from that of the onset of detumescence.  In one case the explosion is sought, in the other case it is dreaded; but in both cases there is a retarded muscular tension,—­in the one case involuntary, in the other case voluntary—­maintained at a point of acute intensity, and in both cases the muscular irradiations of this tension spread over the whole body.

The increased motor irritability of the state of detumescence somewhat resembles the conditions produced by a weak anaesthetic and there is some interest in noting the sexual excitement liable to occur in anaesthesia.  I am indebted to Dr. J.F.W.  Silk for some remarks on this point:—­

“I.  Sexual emotions may apparently be aroused during the stage of excitement preceding or following the administration of any anaesthetic; these emotions may take the form of mere delirious utterances, or may be associated with what is apparently a sexual orgasm.  Or reflex phenomena connected with the sexual organs may occasionally be observed under special circumstances; or, to put it in another way, such reflex possibilities are not always abolished by the condition of narcosis or anaesthesia.

“II.  Of the particular anaesthetics employed I am inclined to think that the possibility of such conditions arising is inversely proportionate to their strength, e.g., they are more frequently observed with a weak anaesthetic like nitrous oxide than with chloroform.

“III.  Sexual emotions I believe to be rarely observable in men, and this is remarkable, or, I should say, particularly noticeable, for the presence of nurses, female students, etc., might almost have led one to expect that the contrary would have been the case.  On the other hand, it is among men that I have frequently observed a reflex phenomenon which has usually taken the shape of an erection of the penis when the structures in the neighborhood of the spermatic cord have been handled.

“IV.  Among females the emotional sexual phenomena most frequently obtrude themselves, and I believe that if it were possible to induce people to relate their dreams they would very often be found to be of a sexual character.”

Much more important than the general motor phenomena, more purposive though involuntary, are the specifically sexual muscular movements.  From the very beginning of detumescence, indeed, muscular activity makes itself felt, and the peripheral muscles of sex act, according to Kobelt’s expression, as a peripheral sexual heart.  In the male these movements are fairly obvious and fairly simple.  It is required that the semen should be expressed from the vesiculae seminales,