306 LEPROSY 



anterior chamber of the eye with leprous material, the cells in 

 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, and also that the picture of 

 cells stuffed with bacilli has also been obtained by the injec- 

 tion of acid-fast saprophytes. It, would accordingly be a mistake 

 to place much reliance on this' point. 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 Rost'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 of a titre, I'd per cent, alkaline to phenol-phthaiein, andl part 

 of a 2 per cent, solution of tryptophane or cysteine ; (b) agar, 1 per cent, 

 alkaline, is planted with fragments of leprous tissue and a non-sporing 

 proteolytic bacterium. After ten days or two weeks the culture is ex- 

 posed to a temperature of 60° C. for half an hour, this being sufficient 

 to kill the hydrolysing bacterium but not the leprosy bacilli. The 

 cultures are then incubated further. 



Bayon uses » 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 

 was given by G. 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 



