CULTIVATION OF LEPROSY BACILLUS 313 



the nodules containing numerous bacilli. These results have 

 been generally called in question, but in view of recent work it 

 is quite possible that the lesions were really of leprous nature. 

 Sugai has found that the Japanese dancing-mouse is com- 

 paratively susceptible to inoculation with leprous material and 

 Duval has confirmed this observation. The experiments of 

 Kedrowski and Bayon have already been referred to. It is to 

 be noted, however, that in all these cases success is only obtained 

 in a certain proportion of cases. Experiments have also been 

 performed on monkeys, but the results cannot be regarded as 

 conclusive. 



Media. Of the various media used by different workers the following 

 may be given as examples. Williams used a fluid medium which is a 

 modification of Eost's original medium, composed of Lemco broth 250 c.c., 

 distilled water 250 c.c., milk 20 c.c. In addition to cultures along with 

 various bacteria, Duval recommends the following : (a) 2 parts of 2 per 

 cent, agar, 1*5 per cent, alkaline to phenol-phthalein, and 1 part of a 

 2 per cent, solution of tryptophane or cysteine ; (&) egg albumen or human 

 blood serum, inspissated at 70 C., is inoculated with small fragments 

 of leprous tissue and then bathed with a 1 per cent, solution of trypsin. 



Bayon uses a fish-agar medium, composed of equal parts of a watery 

 extract of fishes' muscle, rendered sterile by filtration, and 4 per cent, 

 ordinary agar. 



It is interesting to note that a disease occurs under natural 

 conditions in rats which presents many points of close similarity 

 to leprosy. It is very widespread, having been observed in 

 Europe, Asia, America, and Australia; an excellent description 

 has been given by Dean. In this affection there are lesions 

 in the skin which resemble those in leprosy, and the cells con- 

 tain enormous numbers of an acid-fast bacillus. The disease 

 can be transmitted to rats by inoculation with the tissue juices 

 containing the bacilli, but not to animals of other species. 

 The relations of this affection to human leprosy have not yet 

 been worked out, but the facts recently obtained regarding the 

 transmission of leprosy to animals suggest the possibility that 

 the two diseases may be the same ; at any rate they are very 

 closely allied. Bayon claims to have cultivated the bacillus of 

 rat leprosy and finds that it is practically identical, as regards 

 both cultural characters and pathogenic effects, with the organism 

 obtained from the human disease. 



Nastin. This substance has been pretty extensively used in the treat- 

 ment of leprosy and certain favourable effects have been recorded. It is 

 a crystallisable neutral fat, composed of a high molecular fatty acid and 

 glycerin, and was extracted by Deycke and Reschad by means of ether 

 and alkaline alcohol from an acid-fast streptothrix obtained from a case of 



