LEPROSY BACILLUS 71 



formation. In subcultures it is smaller, being in the 

 second or third generation about the same size as the 

 tubercle bacillus. Tt will not grow on ordinary media, 

 but Twort not only devised a medium (of glycerinated 

 eggs mixed with dried, dead, acid-fast bacilli) but also 

 prepared an effective diagnostic vaccine from the cultures. 

 Twort and Ingram incline to the view that the causative 

 organism of Johne's disease in sheep is the same as that 

 of cattle. Besides the animals mentioned only the goat 

 seems affected by injections of the organism. Infected 

 cattle are said to react to avian tuberculin. 



The Leprosy Bacillus. 



Morphology. TheJ5. leprce is a long slender rod, usually 

 straight, with more or less pointed extremities. So far 

 as is known, it is non- motile, and produces no spores. 

 It is Gram-positive and acid-fast, although it stains more 

 rapidly and decolorises more quickly than the tubercle 

 bacillus. Large numbers of the bacilli are found, but a 

 large proportion, especially in the older lesions, are dead. 

 By Ziehl's method, using 20 per cent, nitric acid, and 

 counter-staining with polychrome blue, young bacilli are 

 stained red, older bacilli violet, and granular bacilli blue. 



Kedrowsky found a diphtheroid leprosy organism which 

 was not acid-fast. Bayon, the Research Bacteriologist 

 at Robben Island, thinks it to be a stage in the develop- 

 ment of the typical bacillus. A disease similar to leprosy 

 may be found in rats in most parts of the globe. Some- 

 times this runs to a glandular type, sometimes to a skin 

 affection; acid-fast bacilli indistinguishable from typical 

 leprosy bacilli are present in enormous numbers, and 

 Dean has found an organism similar to Kedrowsky' s 

 bacillus in cultures. 



Culture. Peptone glycerin serum, human blood-serum, 

 fish broth, placental juice glycerin agar (Bayon), symbiotic 

 culture with amoebsc (Clegg), and eggs have been stated 

 to allow the growth of the bacillus. 



Inoculation. Several workers have reported successful 

 attempts to inoculate man, monkeys, and white mice, 

 but the results are much criticised. Bayon, however, 

 says that Kedrowsky 's diptheroid produces leprous 

 lesions in the rabbit, rat, and mouse, and that the result- 

 ing lesions are similar to those caused by certain strains 



