Weafficr, Jl'afcr ami Disease. 25 



that excess of heat may produce disease and destroy life, but 

 that direct effect is rare in conditions of daily life. Usually a 

 predisponent intervenes to complete the connection. In- 

 stances of Summer or hot weather diseases are Asiatic cholera, 

 cholera infantum, heat stroke, yet they are largely more fatal 

 under the influence of bad habits and various other predis- 

 posing causes. Indirectly, heat will develop various toxic 

 substances in food, and then serious attacks of illness may 

 result, as in cheese, fish and ice cream poisoning. 



It will be a familiar statement to most people that neural- 

 gias, headaches and rheumatic pains are importantly related 

 to the meteorological elements above enumerated. Probably 

 the most complete effort ever made to differentiate the factors 

 most concerned in this result is the one initiated over fifteen 

 years ago, by Dr. Weir Mitchell, of Philadelphia, with Captain 

 Catlin, of the United States Army, as his patient, and carried 

 on since then with infinite patience by the Captain. In 1864 

 he was wounded below the knee and the leg amputated. As 

 happens at times, it left what is known as a neuralgic stump. 

 He has ever since suffered neuralgic attacks. He has, within 

 a year, given the medical profession and others the results of 

 his long work. We herewith give his main conclusions. He 

 has platted his observations on a system of curves, in connec- 

 tion with curves of weather observation : "The comparison 

 of the weather elements, such as pressure, temperature, force 

 of wind, humidity — relative and absolute, days of rain, depth 

 of rain, hours of sunshine, number of storms and ozone with 

 pain, covers a period in no case of less than five years. Of 

 these the increasing temperature curve, the hours of sunshine 

 curve, and the absolute vapor curve, operate to diminish pain, 

 while all the others are identified more or less with pain." 

 During great magnetic storms pain of unusual intensity pre- 

 vailed. " Maximum pain bears a direct proportion to storm 

 frequency', and an inverse proportion to temperature and 

 elastic force of vapor, and minimum pain bears an inverse 

 proportion to .storm frequency, and a direct to temperature 

 and ela.stic force of vapor; while depth of rain accompanies 

 the number of storms and maximum pain. Charts of relative 

 storm frequency and geographical pain charts are thus related. 

 He found that the eastern edge of the neuralgic crescent lies 



