that the phenomena of seasonal periodicity
in crimes may possess a real significance in relation to sexual
periodicity. If, as is possible, the occurrence of spring and
autumn climaxes of criminal activity is due less to any special
exciting causes at these seasons than to the depressing
influences of heat and cold in summer and winter, it may appear
reasonable to ask whether the spring and autumn climaxes of
sexual activity are not really also largely due to a like
depressing influence of extreme temperatures at the other two
seasons.

Not only is there periodicity in criminal conduct, but even within the
normal range of good and bad conduct seasonal periodicity may still be
traced. In his _Physical and Industrial Training of Criminals_, H.D. Wey
gives charts of the conduct of seven prisoners during several years, as
shown by the marks received. These charts show that there is a very
decided tendency to good behavior during summer and winter, while in
spring (February, March, and April) and in autumn (August, September and
October) there are very marked falls to bad conduct, each individual
tending to adhere to a conduct-curve of his own. Wey does not himself
appear to have noticed this seasonal periodicity. Marro, however, has
investigated this question in Turin on a large scale and reaches results
not very dissimilar from those shown by Wey's figures in New York. He
noted the months in which over 4,000 punishments were inflicted on
prisoners for assaults, insults, threatening language, etc., and shows the
annual curve in Tavola VI of his _Caratteri dei Delinquenti_. There is a
marked and isolated climax in May; a still more sudden rise leads to the
chief maximum of punishment in August; and from the minimum in October
there is rapid ascent during the two following months to a climax much
inferior to that of May.

The seasonal periodicity of bad conduct in prisons is of interest
as showing that we cannot account for psychic periodicity by
invoking exclusively social causes. This theory of psychic
periodicity has been seriously put forward, but has been
investigated and dismissed, so far as crime in Holland is
concerned, by J.R.B. de Roos, in the Transactions of the sixth
Congress of Criminal Anthropology, at Turin, in 1906 (_Archivio
di Psichiatria_ fasc. 3, 1906).

The general statistics of suicides in Continental Europe show a very
regular and