CULTIVATION OF LEPEOSY BACILLUS 305 



the bacilli occurring in large numbers within rounded cells. 

 This organism grows very slowly and produces an irregular 

 whitish growth of moist appearance closely resembling that of 

 the avian tubercle bacillus. Bayon has confirmed Kedrowski's 

 results. Clegg grew a small acid-fast, bacillus on plain agar 

 medium along with amoebae and symbiotic bacteria, and then 

 by killing the contaminating organisms by means of heat, 

 obtained a pure growth of a chromogenic acid-fast bacillus. 

 Duval following out this work obtained confirmatory results, 

 but in addition to Clegg's bacillus he cultivated a slowly 

 growing non-chromogenic bacillus which only grew on special 

 media (vide infra). This latter he believes to be probably the 

 causal organism. He lays stress especially upon its very slow 

 growth, the colonies after 8-10 months being about the size of 

 those of the influenza bacillus, and upon its requiring the presence 

 of the products of protein digestion. Twort also claims to have 

 cultivated the organism on glycerin egg-medium containing dead 

 tubercle bacilli in the proportion of 1 per cent. Rost and 

 Williams have cultivated a pleomorphous organism, a strepto- 

 thrix, which may appear in the form of bacilli or branched 

 filaments, and both of these forms may be acid-fast or non-acid- 

 fast. Their organism, it is to be noted, however, grows com- 

 paratively rapidly, growth being visible within a week, whilst in 

 the case of the organisms of Kedrowski, Duval, and Twort, 

 growth' only appears after several weeks. Furthermore, the 

 organisms of DuvaJ and Twort appear only in the bacillary form, 

 whilst those of the other observers mentioned show pleomor- 

 phism. Bayon has compared the pathogenic properties of the 

 bacilli cultivated by different workers, and finds that only 

 Kedrowski's bacillus and that cultivated by himself, which he 

 regards as the same organism, produce in animals lesions similar 

 to those of leprosy, the cells in the lesions being stuffed with 

 bacilli, and there appears to be no doubt that in his preparations 

 a multiplication of the organism has taken place. He also finds 

 that only these two strains give a distinct deviation of comple- 

 ment (p. 127) when tested with the serum of leprous patients. 

 It is quite clear that the organisms cultivated by various workers 

 and claimed to be leprosy bacilli present essential differences. 

 At present it is not possible to express any definite opinion on 

 the subject. 



For a long time attempts to transmit leprosy to the lower 

 animals were unsuccessful. The only exception to this statement 

 is afforded by the experiments of Melcher and Orthmann, who 

 produced nodules in the organs of rabbits after inoculating the 



