5 2 THE CAUSATION OF DISEASE. 



Is there any evidence that a rhythm depending npon the 

 seasons takes place in man? It is, a priori, highly improbable 

 that man should be exempt from a principle which operated so 

 palpably in his not very remote ancestors. I believe Dr. Lay- 

 cock was the first to teach that the skin exhibits distinct 

 peculiarities at the different seasons. It seems to be generally 

 acknowledged that the sexual instinct is most active during the 

 spring time, and owing to the close connection between the 

 sexual and cutaneous systems, one would expect to find a 

 peculiar condition of the skin in the spring, and such undoubt- 

 ably is the case. 



Dr.Creighton Brown* says " it is certain that the seasons have 

 still a powerful hold upon the human organism. There is a 

 gain of body weight in winter and a loss in summer, and vital 

 statistics show that each season has diseases which may be 

 called peculiarly its own," and he alludes to the excitement of 

 the nervous system which occurs at the time of spring, quoting 

 the lines of Tennyson — 



" In the Spring a livelier iris brightens on the wing of dove ; 

 In the Spring a young man's fancy lightly turns to thoughts of love." 



At this time of the year nervous diseases abound — crime and 

 insanity increase ; " crimes against the person are most 

 numerous in spring and early summer, when the stags' horns 

 are budding and his aggressive instincts are most pronounced ; 

 while crime against property are most numerous in autumn 

 and summer, when squirrels lay by their stores." And in this 

 connection it would be interesting to discover at what period 

 of the year rape is most frequent. Creighton Brown further 

 observes that many children in springtime exhibit " a restless- 

 ness and excitability, a perversity and irascibility of temper, or a 

 listlessness and indisposition to exertion that are not displayed 

 at other times." 



Now, it may be thought that these organic rhythms are 

 entirely due to the yearly rhythm in the external -body-E ; it is, 

 however, very probable that they tend to occur independently of 

 this external rhythm, seeing that a structure may be educated 



* Article, Education and the Nervous System : " The Book of Health," 

 London, p. 315. 



