2o THE POPULAR SCIENCE MONTHLY 



We have various methods for approaching the cancer problem. We 

 can observe the frequency with which human cancer appears, its symp- 

 toms, and conditions which precede it. We can study the finer struc- 

 ture and mode of development of cancer with the microscope on pieces 

 of tumor which have been excised. We can study cancer from a com- 

 parative point of view, its occurrence in animals and plants. The com- 

 parative study leads to the experimental investigation of cancer in 

 animals. 



1. Frequency, Distribution, Varieties of Human Cancer 



Cancer among man is found in all countries where a closer search 

 for it has been instituted. The frequency with which it occurs differs, 

 however, very much among people living under the ordinary conditions 

 of present civilization in Europe and America and among races or 

 nations living under more primitive conditions, especially in Africa and 

 Asia. 



If we consider first the former category we find that approximately 

 3.1-5 per cent, of all human beings die from cancer. We are struck by 

 the relative uniformity in the percentage of deaths from cancer, which 

 indicates that within certain limits the conditions causing cancer are 

 relatively constant and uniformly distributed over the civilized world. 

 In this respect cancer resembles certain diseases which are caused by 

 organisms evenly distributed over wide areas and to diseases primarily 

 due to internal factors and not or only secondarily to parasitic agencies, 

 while it differs from such diseases as smallpox, bubonic plague and 

 poliomyelitis which are very irregular in their appearance. 



If we compare the death rate from cancer in various countries we 

 find the following figures: In a population of 10,000 die from cancer 

 each year : in Switzerland 13.2, Norway 10, Holland 10.1, England 9.1, 

 Austria 7.8, France 7.6, Prussia 7.1, Italy 6.1, Spain 4.8, Algiers (Euro- 

 pean inhabitants) 3.2. The death rate is also relatively low in Kussia, 

 Hungary, Servia, Jamaica and Ceylon. In Kyoto (Japan) it is approxi- 

 mately like Austria 7.9 per 10,000 inhabitants. On the whole the death 

 rate from cancer is low in the countries around the Mediterranean. 



In the United States in an area comprising one half of the popula- 

 tion, the death rate per 10,000 inhabitants was (according to a report 

 by the Health Commissioner of Pennsylvania (Dr. S. C. Dixon), 7.31 in 

 1907; the death rate in the United States is therefore very similar to 

 that of Germany and Austria. Approximately 75,000 people die from 

 cancer in one year in the United States and about half a million in the 

 civilized world (F. L. Hoffman). If we consider only persons over 45 

 years old, considerably more people in the registered area of the United 

 States die from cancer than from tuberculosis. Between the age of 45 

 and 60 years almost 7 per cent, of the male and 16 per cent, of the 

 female population die in this country from cancer. 



