June 10, 1005.] 



SCIENCE. 



909 



turn to the patient and exact studies of 

 the environment, such as the chemists and 

 physicists began, and have in some meas- 

 ure continued, since the middle of the nine- 

 teenth century. These studies will be 

 directed largely to further knowledge and 

 control of the environment, but they will 

 not end there, for personal hygiene, owing 

 to recent advances in physiology, is to-day 

 one of the most inviting fields for work 

 and education, and I hardly need to point 

 out to a company of experts that the proper 

 care and right use of the individual human 

 mechanism reacts favorably and funda- 

 mentally upon the public health no less 

 truly or effectively than an improved con- 

 dition of the environment or of the public 

 health tends to promote the welfare and 

 long life of the individual. 



The sphere of hygiene may be divided, 

 as it often is, into the two hemispheres, 

 public hygiene and personal hygiene, or it 

 may be cut into one portion dealing chiefly 

 with the human mechanism and its opera- 

 tion {personal hygiene), and another por- 

 tion dealing chiefly with the environment 

 of that mechanism {sanitation). The 

 time has gone by when any one person can 

 safely undertake to deal with the whole 

 sphere of hygiene. The physiologist and 

 the physician must in the future leave to 

 the architect and the sanitary engineer 

 such subjects as housing, heating and venti- 

 lation, water supply and sewerage, pre- 

 cisely as the sanitary engineer has never 

 presumed to deal with foods and feeding, 

 vaccines and antitoxins, exercise, sleep and 

 rest. The former subjects deal chiefly with 

 the control of the environment, the latter 

 subjects chiefly with the control of the in- 

 dividual, and sanitation and hygiene must 

 henceforward be regarded as separate 

 hemispheres of the science of health. 



The science of architecture, if under this 

 head we include the principles of building 



construction, and the heating and ventila- 

 tion of buildings, has done and is doing 

 much of interest and importance to the 

 student of public health science. For my 

 own part, I am continually more and more 

 impressed with the fact that the air supply, 

 especially for the modern civilized and too 

 often sedentary form of mankind, is in the 

 long run quite as important as the water 

 supply, the milk supply or any other 

 supply. Surely, we can not be too careful 

 of the purity of a substance which we 

 take into our bodies oftener, and in larger 

 volume, than any other, and which has 

 come, rightly no doubt, and as the result 

 of long and painful experience, to be 

 known as the very breath of life. I am 

 well aware that human beings may sur- 

 vive and seemingly thrive, even for long 

 periods, in bad air, but I am certain that 

 for the best work, the highest efficiency, 

 the greatest happiness and the largest life, 

 as well as for perfect health, the very best 

 atmosphere is none too good. Hence I 

 believe that the permeability of the walls 

 of houses and other buildings, and the 

 heating and ventilation of dwellings, school 

 houses, churches, halls and other public 

 places, require, and in the near future 

 will receive, a much larger share of our 

 attention than they have to-day. 



In an age characterized by urban life and 

 possessing sky-scrapers, tenement houses 

 and other huge bee-hives, in which human 

 beings aggregating vast numbers spend a 

 large part of their lives, buildings require 

 for their proper construction, lighting, 

 heating, air supply, water supply, gas sup- 

 ply and drainage, the scientific services not 

 only of architects, but of engineers, and 

 such public buildings form one small sec- 

 tion of the aid which modern engineering 

 science is now everywhere rendering to 

 public health science. The present has 

 rightly been called an 'age of engineering,' 



