INFLUENCE OF CLIMATE AND SEASON. 1017 



the head, or violent emotions of terror and other de- 

 pressing passions. The spasmodic tremor of the 

 hands caused by intemperance in the use of 

 ardent spirits, mercury, opium, and other narcotic 

 poisons, is owing to diminished respiration and a 

 vitiated condition of the blood, like the subsultus 

 tendinum of typhus and other malignant fevers, 

 attended with a great loss of vitality and general 

 prostration of strength. 



When the vital energy of the brain is much 

 exhausted, every sudden impression, whether by 

 sight, hearing, or touch, causes the whole frame 

 to start, and, in many cases, brings on repeated 

 spasms, which, in persons of extremely shattered 

 nerves, are induced by the shutting of a door, or 

 by the slightest current of air. At the same 

 time, it is equally manifest, that in cases of 

 hydrophobia and traumatic tetanus, spasms are 

 caused by the irritation of a wounded nerve, in 

 the same way that pricking the nerve of a frog 

 excites involuntary or spasmodic contraction of 

 the muscles. 



The convulsions of infants are far more preva- 

 lent, and require more prompt treatment, in hot 

 climates than in the middle latitudes, and more 

 so in the latter during summer, when the atmos- 

 phere is in a rarefied and impure state, than 

 during winter, especially in large towns, and 

 crowded or ill ventilated dwellings. But cold 

 and moisture are by far the most general ex- 



