770 Leprosy 



possibly the avian stain. Sometimes when the medium is 

 devoid of water of condensation, the growth is dry and oc- 

 casionally wrinkled, though it is easily removed from the 

 surface of the medium. 



"The chromogenic property of lepra cultures is a constant 

 and characteristic feature of the rapidly growing strains. 

 The color varies in the degree of intensity depending upon the 

 medium employed. If glycerinated agar (without peptone) is 

 used, the colonies are faint lemon, while on inspissated blood- 

 serum they are deep orange. It is noteworthy that the 

 growth in the tissues and in the first dozen or so generations 

 on artificial media is entirely without pigment." 



Pathogenesis. Melcher and Ortmann* introduced frag- 

 ments of lepra nodules into the anterior chambers of the 

 eyes of rabbits, and observed the death of the animals after 

 some months, with what they considered to be typical lep- 

 rous lesions of all the viscera, especially the cecum ; but the 

 recent careful experiments of Tashiroj show that most of the 

 lower animals are entirely insusceptible to infection with the 

 lepra bacillus, and that when they are inoculated the bacilli 

 persistently diminish in numbers and finally disappear. 



Nicolle | found it possible to infect monkeys with material 

 rich in lepra bacilli taken from human beings. The lesions 

 appeared only after an incubation period that was in some 

 cases prolonged from twenty-two to ninety-four days. The 

 lesions persisted but a short time and the monkeys recovered 

 in from thirty to one hundred and fifty days. 



Clegg and Sugai|| found Japanese dancing mice suscep- 

 tible to infection with leprous material, the micro-organisms 

 not remaining localized at the seat of inoculation, but dissem- 

 inating throughout the animal's body. Their observation 

 has been confirmed by Duval,** who later ff was also able to 

 infect monkeys Macacus rhesus with pure cultures of the 

 organism and produce the typical disease. 



Very few instances are recorded in which actual inocula- 



* "Berliner klin. Wochenschrift," 1885-1886. 



f "Centralbl. f. Bakt. u. Parasitenk." Originale), xxxi, No. 7, p. 

 276, March 12, 1902. 



f "Semaine medicale," 1905, No. 10, p. no. 



"Philippine Journal of Science," 1909, iv, 403. 



|| "Lepra," 1909, vin, 203. 



** "Journal of Experimental Medicine," 1910, xn, 649. 

 tt Ibid., 1911, xiu, 374. 



