622 INFECTION AND IMMUNITY. 



serum and cells of man and animals, by which 

 conclusions as to the defensive powers of the body 

 might be drawn, can not be carried out. It seems 

 probable that all men ar susceptible to leprosy 

 under the proper conditions. Sauton states that 

 children of from 4 to 5 years are particularly 

 liable to infection. Other conditions which may 

 increase suspectibility are of a conjectural nature. 

 It is possible that leprosy predisposes to tuber- 

 culous infection. 



The condition in leprosy seems to be that of an 

 organism of low virulence against which the body 

 possesses no decisive protective agency. The reac- 

 tions for the most part are of a local nature, involv- 

 ing the proliferation of connective tissue and blood 

 vessels, and the accumulation of lymphocytes. That 

 phagocytosis by macrophages (lymphocytes, con- 

 nective tissue, endothelial and ganglionic cells) is 

 a factor which antagonizes the proliferation of the 

 bacilli is suggested by the large number of bacilli 

 which are found in these cells. 



prophylaxis. The principles of prophylaxis may be illustrated 

 by citing the practices in Norway. Originally all 

 lepers were confined to institutions. At the pres- 

 ent, however, only indigent lepers and those who 

 can not be suitably cared for at home are required 

 to enter an asylum, where they live under the best 

 hygienic conditions. Other patients are allowed to 

 remain at home, with the understanding that they 

 sleep alone and, if possible, have separate rooms, 

 that their clothing, linen and eating utensils be 

 used by no one else, and that proper precautions 

 be taken in the washing of linen. Dressings and 

 bandages must be burned. Under these regulations 



