RETROSPECT AND PROSPECT 377 



Without citing similar statistics which may be derived from 

 other states and most countries of the globe, it may be asked 

 if these data really suffice to prove that cancer is actually in- 

 creasing. In interpreting most statistics of the increase of cancer, 

 allowance must be made for the changing age distribution of the 

 population. Both the decline of the birth rate and the increasing 

 duration of life make the proportion of people of middle age and 

 beyond relatively higher. Hence a larger proportion of the 

 population would now be liable to be affected by cancer than in 

 previous years. 



Undoubtedly this circumstance explains a part of the statistical 

 increase of cancer, but it does not suffice to explain all of it. 

 Willcox in fact attributes only about one-third of the reported 

 increase to this cause. If we study the death rate for any partic- 

 ular age, say 55, estimating the proportion dying of cancer to all 

 the population of that age we frequently find that the cancer 

 death rate has increased materially in the last few years. This is 

 true for most ages in the United States between the periods 

 1903-07 and 1908-12 according to the United States Census. 

 Data from the life insurance companies of Austria over the 

 period from 1876 to 1900 fail to show any consistent trend of 

 cancer mortality for most age groups. 



Dr. F. L. Hoffmann on the basis of his extensive and valuable 

 collection of statistics on cancer mortality from several countries 

 has concluded that there is an actual increase of cancer which 

 cannot be explained either by changes in age distribution of the 

 population or by improvements in the accuracy of diagnosis. 

 Professor Willcox, however, has made a critical study of the prob- 

 lem and has come to a quite different conclusion. Most of the 

 statistical increase of cancer which cannot be explained by the in- 

 creasing proportion of people of middle or old age may be ac- 

 counted for, according to Willcox, by improvements in diagnosis, 

 and the greater proportion of deaths which are now certified by 

 competent physicians. The layman seldom reports cancer as a 

 cause of death. Where physicians are relatively plentiful more 

 deaths from cancer are put on record. Fewer deaths are now 



