152 



science:. 



[Vol. vm., No. 184 



To illustrate the possibilities in this direction, I 

 will call your attention to some peculiarities in 

 the distribution of deaths from certain causes in 

 different parts of the United States, and for this 

 purpose I shall make use of the data from our last 

 census, taken in 1880. We have no general and 

 uniform system of registration of births and 

 deaths. The larger cities, and about half-a-dozen 

 states, have such a system, but for much the 

 larger portion of the country the only means 

 which we have for determining differences in 

 amount or causes of mortality in different locali- 



tion, although they do not furnish^'definite and 

 scientific answers. 



Take, for instance, the map of the United 

 States upon which, by varying shades of color, is 

 shown the proportion of deaths reported as due to 

 cancer, as compared with the reported deaths 

 from all causes. (Chart ii.) 



The mortality from cancer in the United States 

 is proportionately greatest in the New England 

 states, somewhat less so in New York and Penn- 

 sylvania, and it causes the least proportion of 

 deaths in the Mississippi valley and the south 



Chart II. — showing the distribution of deaths from cancer as compared with total deaths form known causes. 



ties is through the census, which is taken once in 

 ten years. The data thus obtained with regard to 

 deaths are imperfect, because when these are col- 

 lected only at the end of the year, about 30 per 

 cent of the deaths are unrecorded ; and they are 

 inaccurate, because the reports of the causes of 

 death are not furnished by persons competent to 

 give reliable information with regard to them. 

 Nevertheless, these data are the best that we have; 

 and although for a large part of the country they 

 do not give us the actual number of deaths from 

 any cause or set of causes, they do furnish some 

 interesting information with regard to the relative 

 prevalence and importance of certain causes, and 

 suggest questions and lines for future investiga- 



generally. The proportion of deaths from cancer 

 in the United States is somewhat greater than it is 

 in England ; but it is not possible to make any 

 accurate comparisons in this respect. Now why 

 are the shades on this map so dark in the north- 

 east and so light in the south ? In the first place, 

 cancer is a disease the mortality from which stead- 

 ily increases with advanced age, as you may see 

 from this diagram. Hence, cancer causes a 

 higher proportion of mortality in those locali- 

 ties which have the greatest proportion of popu- 

 lation living at advanced ages, and in the 

 United States these localities are the New Eng- 

 land states, as you will see by this map. Another 

 explanation of the peculiar shading of the cancer 



