not always, has the effect of stopping the excitement,
and a very long walk sometimes does the same. When the
excitement gets to a height, it is always followed by about a
week of stupid depression." In the same article Clouston remarks:
"I have for a long time been impressed with the relationship of
the mental and bodily alternations and periodicities in insanity
to the great physiological alternations and periodicities, and I
have generally been led to the conclusion that they are the same
in all essential respects, and only differ in degree of intensity
or duration. By far the majority of the cases in women follow the
law of the menstrual and sexual periodicity; the majority of the
cases in men follow the law of the more irregular periodicities
of the _nisus generativus_ in that sex. Many of the cases in both
sexes follow the seasonal periodicity which perhaps in man is
merely a reversion to the seasonal generative activities of the
majority of the lower animals." He found that among 338 cases of
insanity, chiefly mania and melancholia, 46 per cent, of females
and 40 per cent, of males showed periodicity,--diurnal, monthly,
seasonal, or annual, and more marked in women than in men, and in
mania than in melancholia,--and adds: "I found that the younger
the patient, the greater is the tendency to periodic remission
and relapse. The phenomenon finds its acme in the cases of
pubescent and adolescent insanity."

Conolly Norman, in the article "Mania, Hysterical" (Tuke's
_Psychological Dictionary_), states that "the activity of the
sexual organs is probably in both sexes fundamentally periodic."

Krafft-Ebing records the case of a neurasthenic Russian, aged 24,
who experienced sexual desires of urologinic character, with fair
regularity, every four weeks (_Psychopathia Sexualis_), and Naecke
mentions the case of a man who had nocturnal emissions at
intervals of four weeks (_Archiv fuer Kriminal-Anthropologie_,
1908, p. 363), while Moll (_Libido Sexualis_, Bd. I, pp. 621-623)
recorded the case of a man, otherwise normal, who had attacks of
homosexual feeling every four weeks, and Rohleder (_Zeitschrift
fuer Sexualwissenschaft_, Nov., 1908) gives the case of an
unmarried slightly neuropathic physician who for several days
every three to five weeks has attacks of almost satyriacal se