SUSCEPTIBILITY TO INFECTION 27 



measles, of influenza, or of bronchitis, in which dis- 

 eases there is a catarrhal inflammation of the bron- 

 chial tubes which appears to favour infection by the 

 specific micrococcus which is the usual cause of pneu- 

 monia. The victims of chronic alcoholism are es- 

 pecially subject to pneumonia. 



Certain occupations increase the susceptibility to 

 certain infectious diseases. Thus pulmonary con- 

 sumption is more likely to be developed in those who 

 lead an indoor life, whose occupation has a tendency 

 to prevent full expansion of the lungs tailors, seam- 

 stresses ; and in persons who are compelled to breathe 

 a dust-laden atmosphere factory hands, grinders, 

 etc. Susceptibility to pneumonia, influenza, tonsil- 

 litis, and diseases of the air passages generally is 

 increased by living in over-heated apartments. Ex- 

 posure to cold, per se, is not likely to increase the 

 susceptibility to such infections in individuals who 

 are habituated to living in the open air, such as sail- 

 ors, hunters, soldiers living in tents, etc. 



