ne marked and
prolonged rise every month or five weeks, averaging three days,
occasional lesser rises appearing irregularly and of shorter
duration. These observations are only made in three cases, and I
have no proof that they refer to the sexual appetite" (Campbell
Clark, "The Sexual Reproductive Functions," Psychological
Section, British Medical Association, Glasgow, 1888; also,
private letters). Hammond (_Treatise on Insanity_, p. 114) says:
"I have certainly noted in some of my friends, the tendency to
some monthly periodic abnormal manifestations. This may be in the
form of a headache, or a nasal haemorrhage, or diarrhoea, or
abundant discharge of uric acid, or some other unusual
occurrence. I think," he adds, "this is much more common than is
ordinarily supposed, and a careful examination or inquiry will
generally, if not invariably, establish the existence of a
periodicity of the character referred to."

Dr. Harry Campbell, in his book on _Differences in the Nervous
Organization of Men and Women_, deals fully with the monthly
rhythm (pp. 270 et seq.), and devotes a short chapter to the
question, "Is the Menstrual Rhythm peculiar to the Female Sex?"
He brings forward a few pathological cases indicating such a
rhythm, but although he had written a letter to the _Lancet_,
asking medical men to supply him with evidence bearing on this
question, it can scarcely be said that he has brought forward
much evidence of a convincing kind, and such as he has brought
forward is purely pathological. He believes, however, that we may
accept a monthly cycle in men. "We may," he concludes, "regard
the human being--both male and female--as the subject of a
monthly pulsation which begins with the beginning of life, and
continues till death," menstruation being regarded as a function
accidentally ingrafted upon this primordial rhythm.

It is not unreasonable to argue that the possibility of such a
menstrual cycle is increased, if we can believe that in women,
also, the menstrual cycle persists even when its outward
manifestations no longer occur. Aetius said that menstrual
changes take place during gestation; in more modern times, Buffon
was of the same opinion. Laycock also maintained that menstrual
changes take place during pregnancy (_Nervous Diseases of Women_,
p. 47). Fliess