408 INFECTIVE DISEASES. 



in the anterior chamber of the eye of rabbits. The animals died 

 after some months with extensive deposits in the coecum, lymphatic 

 glands, spleen, and lungs. 



These tubercles varied in size from a pin's head to a millet seed, 

 and contained bacilli, resembling leprosy bacilli in their staining 

 reactions. The question naturally arises whether the lesions were 

 really indicative of leprosy or tuberculosis. Until the experi- 

 ments are independently confirmed, and the result of inoculation 

 differentiated from tuberculosis, it would be rash to accept these 

 experiments as conckisive. 



It has been suggested that tuberculosis and leprosy are identical. 

 There is a similarity in the bacilli and in the lesions of leprosy and 

 tuberculosis, the injection of tuberculin produces a reaction in leprosy 

 nodules, and many lepers die from tubercular disease of the lung. 

 But while tuberculosis is very readily transmitted to guinea-pigs 

 and rabbits by inoculation of fragments of tubercular tissue, leprosy 

 is inoculable, if at all, in most exceptional instances. The bacilli 

 of tubercle are cultivated with the greatest facility, the bacilli of 

 leprosy, if at all, only with exceptional difficulty; tubercle bacilli 

 are found in giant cells, leprosy bacilli in the so-called leprosy 

 cells. Leprosy bacilli are straighter than human tubercle bacilli,^ 

 and differ slightly in their behaviour to staining reagents. On 

 the other hand, the morphological differences are not greater than 

 those existing between different forms of tubercle bacilli obtained 

 from tuberculosis in animals and birds. It would be premature 

 to regard leprosy as a variety of tubercle until cultivations of 

 the bacillus have been obtained, and carefully compared with 

 those of the tubercle bacillus. Differences in morphological details 

 and results of inoculation would then carry less weight as a means 

 of differentiation. 



The tubercular pneumonia of lepers would be regarded, if the 

 bacilli are identical, as a development of leprosy in the lungs, and 

 not, as at present, a result of double infection with tuberculosis. 



Methods of Examining the Bacillus of Leprosy. 



Cover-glass preparations may be made in the ordinary way, or by a 

 special method, which consists in clamping a nodule with a pile clamp 

 untU a state of anaemia of the tissue is produced. On pricking with a 

 needle or sharp knife a drop of clear liquid exudes, from which cover- 

 glass preparations may he made, and stained by Neelsen's method. 



For sections the author prefers Neelsen's method and methylene-blue. 

 They can also be stained by Gram's method, which, as a rule, brings out 

 very clearly the beaded appearance of the bacilli. 



