Weather, Water and Disease. 33 



determine the amount of chlorine as a test of sewage impuri- 

 ties, yet the main reliance is to be placed on the bacterial 

 tests, especially with reference to typhoid fever. 



We have thus given an imperfect review of the factors in 

 our environment, pertaining to weather, water and disease, 

 and indicated to some degree how they can injuriously affect 

 the individual. It remains now to consider what opposing 

 forces the individual can bring to ])ear, in order that he may 

 counteract the unfavorable conditions to which his environ- 

 ment may expose him 



It may be said in a general wa}-, that it is a testimony to the 

 successful contest of a nation with the forces of nature where 

 it grows in numbers, without extraneous additions, when the 

 proper proportion between births and deaths is maintained, 

 when it advances in arts and sciences and enjoys all the com- 

 forts of life, when it has been able to control some of the most 

 dangerous forces of nature, and make them minister to its 

 happiness. 



But in this aggregate of life and activit}' the individual 

 must carry on his own struggle for existence, so far as it con- 

 cerns his health. 



The superstructure of life is built mainly on the basis fur- 

 nished b}' heredity. While it ma}- be said that no one is 

 exempt from influences producing disease, yet the liabilities 

 are diminished very much in the case of him or her, who 

 most nearly approaches the physiological standard. This 

 approach can be estimated numerically in a few particulars. 

 Numerous investigations, physiological and clinical, have 

 shown that there is a close relation between pulse, respiration 

 and temperature, expressed generally as 70 to 75 for pulse ; 16 

 to 1 8 for respiratioti, and 9<S>^ for temperature in the adult. 

 Any persistent variation from these figures is reason to sus- 

 pect disease of some sort. They are representative of the 

 important functions of the heart, the lungs and the complex 

 phenomena of nutrition, including chemical and nervous 

 activities. We know that nervous excitement, or shock, will 

 accelerate the movements of the heart and lungs and seriously 

 derange our digestion. Insurance companies have their 

 standards, and may be considered as forming a body of select 

 livers, but they estimate eligibility on the basis of a single 



