Wealher, IVaier and Disease. 37 



family early show predispositions. They diminish the vigor 

 of individuals and open the way for diseases other than that 

 which the predisposition would produce. There is, however, 

 a modifying effect in age, by which the predisposition disap- 

 pears. If an individual, by heredity liable to consumption, 

 gets beyond thirty years of age, his immunit}^ increases each 

 year beyond that time, and with care he maj' escape it entirely. 

 Sometimes old age in such cases brings a decreasing immunity. 



We may allude to another source of weakness in some por- 

 tions of our population. The census returns for 1880 show 

 that we had then a population of over 6,000,000 people foreign 

 born. It is well known that the process of acclimatization 

 makes its subjects more liable to disease, especially in their 

 epidemic forms. The history of cholera, small-pox and 

 scarlet fever in our city shows their greatest infringment on 

 the foreign-born population. This result may be ascribed 

 largely to the climatic changes and want of adjustment to 

 them, which the native population have already secured. 

 Considering the numbers above will give an idea of how much 

 disease may be attributed to that part of our population. 



The summary- of this paper is as follows : An attempt to 

 outline each factor of weather as an opposer to the indi- 

 vidual — for there is no complete harmony between the two. 

 While there is an appreciable influence in each component, it 

 is in its association with one or more besides that we usuajly 

 see and feel it. Types of weather are thus formed. Cold or 

 heat with humidity ; cold with wind. Another, heat and 

 wind and low-air pressure are some of these types. Few 

 efforts have been made to correlate exactly disease with a 

 single factor, or with associated ones. Dr. Mitchell's and 

 Capt. Catlin's are the most scientific and practical ever 

 attempted. Besides these strictly meteorological elements, 

 we have considered the ^etiological effect of accidental impuri- 

 ties of the air and water and ground, such as dust, fog and 

 bacteria. That the microbes of air and water and soil through 

 their products or virus stand in closer causal relations to dis- 

 ease than mere meteorological elements. We have endea- 

 vored to signify, in a limited degree, what the defenses of the 

 individual must be in the struggle — principally good health 

 and certain immunities from liabilities to disease conferred by 



