72 AIDS TO BACTERIOLOGY 



of human tubercle. Couret says that multiplication of 

 the leprosy bacillus occurs in inoculated fish, frogs, turtles, 

 and other cold-blooded animals. 



Pathogenesis. Two types of leprosy are recognised: 

 the nodular (or tubercular), in which the new formation 

 has its seat in the skin or mucous membrane; and the 

 anaesthetic (lepra anaesthetica), in which the nerves are 

 chiefly affected. In the skin variety the hands and face 

 are mostly affected, and larger or smaller swellings appear 

 (red or blue in colour), which become hard. These 

 tubercles consist of granulation tissue, and may ulcerate 

 and cicatrise, producing great deformities. In the 

 anaesthetic form the nerve trunks become the seat of the 

 granulations in the interstitial connective tissue. The 

 spindle-shaped swellings compress and separate the nerve 

 fibres. Besides the anaesthesia, other evidences of inter- 

 ference with nerves, such as eruptions, alterations in 

 pigmentation, and ulceration, frequently occur. 



The leprosy bacillus has been found in most of the 

 tissues and viscera, though it occurs more in the 'liver 

 and spleen than in the kidneys and brain. Tt has been 

 detected in the blood during febrile paroxysms in the later 

 stages. Enormous numbers are found in cutaneous and 

 other nodules, and in the discharges therefrom. Stitt 

 says the earliest lesion is probably a nasal ulcer at the 

 junction of the bony and cartilaginous septum. Scrapings 

 from this ulcer may give an early diagnosis. 



Lepers frequently react to Old Tuberculin and give 

 positive Wassermann tests. The significance of these 

 findings is uncertain, but it has been suggested that nothing 

 more than coexistence of tuberculosis or syphilis re- 

 spectively is indicated. Fletcher (Jour. Hygiene, July, 

 1915) says that lepers give negative luetin reactions and 

 thinks the positive Wassermann due to a cause other than 

 syphilis. According to Stanziale and Serra the Wasser- 

 mann reaction is positive in rabbits which have been 

 successfully inoculated with Kedrowsky's diphtheroid. 



Channels of Infection. The use of fish, especially in 

 the putrid condition, was considered by Hutchinson to 

 be a causative factor, but the disease occurs among the 

 Basutos, who never eat fish, and among the vegetarian 

 Brahmins. David Walsh modifies the idea by pointing 

 out that dried fish, a common article of diet amongst 



