270 Appendix 



Whether or not the leper bacillus has a spore 

 stage is in doubt. Bacilli will not be brought up 

 from a deep interment by earthworms, nor can they 

 come to the surface unaided. But internal inocu- 

 lation of leprosy may occur from eating food contami- 

 nated by insects filled with infected secretions. The 

 insects may have come, by flight or otherwise, from 

 some distance. If fish are contaminated by mosquito 

 larvae, the question is raised as to how these larvae 

 have received the infection. There are two possible 

 methods. The adult may have laid an infected egg, 

 or the larvae may have become infected by devour- 

 ing bacilli liberated in the ponds by disintegrated 

 dead bodies of infected mosquitoes. Leprosy, how- 

 ever, existed in Hawaii before mosquitoes were 

 brought there, which last was accomplished by larvae 

 breeding in the water tanks of American vessels. 

 Before this introduction leprosy was probably spread 

 by fleas. Unquestionably, bloodsucking or secretion- 

 feeding mosquitoes may become infected with bac- 

 teria or their spores. Many of the ingested bacteria 

 may escape destruction and pass out with the faeces 

 in a virulent condition. Probably in some instances 

 the bacteria actually multiply within the bodies of 

 mosquitoes and possibly reach the salivary glands, 

 escaping with the secretion when it is emitted. 



Fleas, known to convey plague bacilli from rats, 

 may also deposit faeces infected with leper bacilli on 

 the mangy sores of dogs, where the bacilli may 

 multiply and reinfect other fleas. The bacilli are 

 known to exist in fleas that have bitten leprous 

 persons. Nuttall, however, claims that fleas do not 



