* 488 BACILLI IN CHRONIC INFECTIOUS DISEASES. 
mation has not been definitely settled. As before remarked, un- 
stained portions, occurring at regular intervals, are seen in the rods in 
stained preparations ; but no satisfactory evidence has been presented 
to show that these are truly reproductive spores. 
Pathogenesis.—The inference that the bacillus above described 
bears an etiological relation to the disease with which it is associated 
is based upon the demonstration of its constant presence in leprous 
tissues—which has now been repeatedly made in various and distant 
parts of the world—and of its absence from the same tissues involved 
in different morbid processes. As it has not been obtained in pure 
cultures, the final proof of such etiological relation is still wanting. 
We have, however, experimental evidence to show that leprous tis- 
sues containing this bacillus are infectious and may reproduce the 
disease. The experiment has been made upon man by Arning, who 
inoculated a condemned criminal subcutaneously with fresh leprous 
tubercles. The experiment was made in the Sandwich Islands, and 
the man was under observation until his death occurred from leprosy 
at the end of about five years. The first manifestations of the disease 
became visible in the vicinity of the point of inoculation several 
months after the experimental introduction of the infectious material. 
Positive results have also been reported in the lower animals by 
Damsch, by Vossius, and by Melcher and Ortmann. The last-named 
investigators inoculated rabbits in the anterior chamber of the eye 
with portions of leprous tubercles excised for the purpose from a 
leper. The animals died from general infection at the end of several 
months, and the characteristic tubercles containing the bacillus were 
distributed through the various organs. 
Wolters (1893) who has made numerous inoculation experiments 
and has made a critical review of all the recorded experimental evi- 
dence, arrives at the conclusion that the comparatively small number 
of successful results reported cannot be accepted as evidence that 
leprosy can be transmitted to the lower animals by inoculation. He 
believes that in some cases the tubercle bacillus has been present in 
the material inoculated and that the infectious process following the 
inoculation was tuberculous and not Jeprous. In inoculations into 
the anterior chamber, in the eyes of rabbits, the considerable number 
of bacilli introduced with the leprous tissue remain and retain their 
staining properties, so that the bacilli originally introduced are found 
in the leucocytes of the inflammatory exudate or granulation tissue 
formed as a result of the introduction of foreign material. Wolters 
also doubts whether the few successful results reported in the culti- 
vation of the lepra bacillus are trustworthy. He has never succeeded 
in his efforts to cultivate the bacillus. 
