180 IMMUNITY 



has been attributed to racial immunity, but Hahn thinks it due to 

 more hygienic living and calls attention to the high death-rate from 

 this disease among the poor, ignorant Jews of Poland and Galicia. 

 Another illustration is the unequal distribution of leprosy among the 

 Kabyles and Arabs of Algeria. The former live in better houses, select 

 better locations for their homes, are not so crowded and are personally 

 more clean. The truth is that the death-rate from infectious diseases 

 has become the best measure of intelligence. The more intelligent a 

 people, the lower the death-rate. 



It should be understood, however, that the death-rate from the 

 infectious diseases is a measure not of individual, so much as of com- 

 munity, intelligence. In this country the wonderful reduction in the 

 death-rate from infectious diseases in the past fifteen years has been 

 confined largely to the great cities. Smaller cities, villages and rural 

 communities have improved but little. The larger cities are establishing 

 effective health departments. Building regulations prevent the con- 

 struction of unsanitary houses, either public or private. Schoolchil- 

 dren are inspected by competent medical men and first cases are 

 detected and isolated. Proper hospitals for the infectious diseases are 

 provided and scientifically administered. The children of the poorest 

 and most ignorant go to sanitary school buildings and when infected, 

 are scientifically treated. The health officer of the smaller city is a 

 joke and that of villages and rural communities exists, for the most 

 part, only in name. 



It was formerly believed that the African is naturally immune to 

 malaria, but more recent and more thorough studies show that this 

 disease is highly prevalent and fatal among the children of that race 

 and that the apparent resistance observed in the adult is due to acquired 

 immunity. In parts of Greece and Italy malaria has been constantly 

 prevalent for more than two thousand years. During that time it has 

 spared no generation and in many localities scarcely any individual, 

 and yet no marked immunity has been inherited. The young of recent 

 generations retain their susceptibility. How this compares with that 

 of the first generation subjected to the infection we cannot say. How- 

 ever, it is undoubtedly true, that resistance to certain specific infections 

 increases after many generations of continuous exposure. The most 

 intelligent physicians of Cuba believed, before the discovery of the 



