The following are the physical causes which are commonly found to operate in producing the suicidal disposition—viz., climate, seasons, hereditary predisposition, cerebral injuries, physical suffering, disease of the stomach and liver complicated with melancholia and hypochondriasis, insanity, suppressed secretions, intoxication, unnatural vices, and derangement of the _primæ viæ_. These causes can only act by influencing sympathetically the brain and nervous system, and in that way interfering with the healthy operations of the mind. Much will, of course, depend upon the physical conformation of the individual exposed to such agents. Should he labour under an hereditary predisposition to insanity, or to suicidal delirium, a very trifling corporeal derangement may call into existence the self-destructive propensity, and _vice versa_. It will be our object to consider _seriatim_ all the physical agents just enumerated. Among the causes of suicide, the foggy climate of England has been brought prominently forward. The specious and inaccurate conclusions of Montesquieu on this point have misled the public mind. The climate of Holland is much more gloomy than that of England, and yet in that country suicide is by no means common. The reader will perceive from the following tabular statement that the popular notion of the month of November being the “suicide’s month” is founded on erroneous _data_. The average number of suicides in each month, from 1817 to 1826, was as follows:— January 213 February 218 March 275 April 374 May 328 June 336 July 301 August 296 September 246 October 198 November 131 December 217 ———— 3133 It has been clearly established that in all the European capitals, when anything approaching to correct statistical evidence can be procured, the _maximum_ of suicide is in the months of June and July; the _minimum_ in October and November. Temperature appears to exercise a much more decided influence than the circumstances of moisture and dryness, storms or serenity. M. Villeneuve has observed a warm, humid, and cloudy atmosphere to produce a marked bad effect at Paris; and that so long as the barometer indicated stormy weather, this effect continued.[44] Contrary, however, to the opinion of Villeneuve, it appears that by far the fewer number of suicides occur in the autumn and winter at Paris, than in the spring and summer. _Number of suicides for seven years._ In Spring 997 In Summer 933 In Autumn 627 In Winter 648 When the thermometer of Fahrenheit ranges from 80° to 90° suicide is most prevalent.