120 ESSENTIALS OF BACTERIOLOGY 



doubtful. Several other serums have been introduced, but 

 none have shown any lasting virtues. 



Lepra Bacillus (Hansen). Origin. In 1880 Armauer 

 Hansen declared, as the result of many years' investigation, 

 that he found a bacillus in all leprous processes. 



Form. Small slender rods, somewhat shorter than tubercle 

 bacilli, otherwise very similar in appearance. 



In the interior of the cell two or three oval spaces are usually 

 seen, not known if spores or otherwise. 



Properties. They are immotile, and do not liquefy the 

 nutrient media. 



Growth. Bordoni-Uffreduzzi have obtained growths upon 

 blood-serum to which peptone and glycerin had been added, 

 but the accuracy of this observation is very doubtful. 



Staining. They resist the decolorizing action of acids, as the 

 tubercle bacilli, but they are easily stained, requiring but a 

 few minutes with the ordinary watery solutions. They take 

 Gram's stain readily. 



Patho genesis. Arning has inoculated prisoners with tissue 

 obtained from leprous patients, and produced true leprosy. 



Rabbits which had been infected through the anterior cham- 

 ber of the eye showed the lepra nodules (containing the lepra 

 bacilli) diffused through various organs, but here again the 

 .results are not wholly satisfactory. 



In man the skin and peripheral nerves are principally affected, 

 but the lymphatic glands, liver, and spleen can also become the 

 seat of the lepra nodules. The lepra cells which compose these 

 nodules contain the bacilli in large numbers. By applying a 

 vesicant to the leprous skin, the serum thereby obtained will 

 contain great numbers of bacilli. This is a simple diagnostic 

 test. 



Method of Infection. Not yet determined; the air, soil, water, 

 and food of leprous districts have been carefully examined with- 

 out result. The nasal secretion is very infectious. 



Syphilis Bacillus of Lustgarten (Smegma Bacillus of 

 Alvarey and Tavel). Lustgarten, in 1885, through a certain 

 staining process, found peculiar bacilli in syphilitic tissues 



