owever, in possession of a much
more extended series of ecbolic observations completed before Nelson's
paper was published, although the results have only been calculated at a
comparatively-recent date. I now propose to present a summary of these
observations, and consider how far they confirm Nelson's conclusions.
These observations cover no less a period than twelve years, between the
ages of 17 and 29, the subject, W.K., being a student, and afterward
schoolmaster, leading, on the whole, a chaste life. The records were
faithfully made throughout the whole of this long period. Here, if
anywhere, should be material for the construction of a menstrual rhythm
on an ecbolic basis. While the results are in many respects instructive,
it can scarcely, perhaps, be said that they absolutely demonstrate a
monthly cycle. When summated in a somewhat similar manner to that adopted
by Nelson in his ecbolic observations, it is not difficult to regard the
maximum, which is reached on the 19th to 21st days of the summated
physiological month, as a real menstrual ecbolic climax, for no other
three consecutive days at all approach these in number of ecboles, while
there is a marked depression occurring four days earlier, on the 16th day
of the month. If, however, we split up the curve by dividing the period of
twelve years into two nearly equal periods, the earlier of about seven
years and the latter of about four years, and summate these separately,
the two curves do not present any parallel as regards the menstrual cycle.
It scarcely seems to me, therefore, that these curves present any
convincing evidence in this case of a monthly ecbolic cycle (and,
therefore, I refrain from reproducing them), although they seem to suggest
such a cycle. Nor is there any reason to suppose that by adopting a
different cycle of thirty days, or of twenty-three days, any more
conclusive results would be obtained.

It seems, however, when we look at these curves more closely, that they
are not wholly without significance. If I am justified in concluding that
they scarcely demonstrate a monthly cycle, it may certainly be added that
they show a rudimentary tendency for the ecboles to fall into a
fortnightly rhythm, and a very marked and unmistakable tendency to a
weekly rhythm. The fortnightly rhythm is shown in the curve for the
earlier period, but is somewhat disguised in the curve for the total
period, because the first climax is spread over two days, the