NATURAL DEATH, PUBLIC HEALTH 229 



and public health have, by all odds, the best case when 

 measured in terms of accomplishment. Man's expecta- 

 tion of life has increased as he has come down through 

 the centuries (c/. Pearson and Macdonell.) A large 

 part of this improvement must surely be credited to his 

 improved understanding of how to cope with an always 

 more or less inimical environment and assuage its asper- 

 ities to his greater comfort and well-being. Tq fail to 

 give this credit would be manifestly absurd. 



But it would be equally absurd to attempt to main- 

 tain that all decline in the death-rate which has occurred 

 has been due to the efforts of health officials, whether 

 conscious or unconscious, as is often asserted and still 

 more often implied in the impassioned outpourings of 

 zealous propagandists. The open-minded student of the 

 natural history of disease knqws perfectly well that a 

 large part of the improvement in the rate of mortality 

 cannot possibly have been due to any such efforts. To 

 illustrate the point, I have prepared a series of illustra- 

 tions dealing with conditions in. the Registration Area 

 of the United States in the immediate past. All these 

 diagrams (Fig^ires 52, 53, and 54) give death-rates per 

 100,000 from various causes of death in the period of 

 1900-1918, inclusive, both sexes for simplicity being taken 

 together. The lines are all plotted on a logarithmic 

 scale. The result of this method of plotting is that the 

 slope trend of each line is directly comparable with that 

 of any oth&r, no matter what the absolute magnitude of 

 the rates concerned. It is these slopes, measuring im- 

 provement in mortality, to which I would especially 

 direct attention. 



