to that upon agar-agar. In puncture-cultures most of the
growth is on the surface in the form of a whitish, or
grayish, or yellowish folded layer. In the depths of the
gelatin the development occurs as a granular rather thick
column. The medium is not liquefied.
Bouillon is not clouded; no superficial growth occurs.
The vegetation occurs only at the bottom of the tube in
the form of a powdery sediment.
Czaplewski found that the bacillus stained well with
Loffler's methylen-blue, and with the aqueous solutions
of the ariilin dyes. It also stains by Gram's method, and
has the same resisting power to the decolorizing action
of mineral acids and alcohol as the lepra bacillus as seen
in tissue. The young bacilli color homogeneously, but
older ones are invariably granular. They are usually
pointed at the ends when young, but may be rounded or
knobbed when older. The more rapidly the bacillus
grows, the longer and more slender it appears.
All attempts to infect the lower animals with leprosy,
either by the purulent matter or solid tissue from lepers,
or by inoculating them with the supposed specific bacilli
that have been isolated, have failed.
Ducrey seems to have cultivated the lepra bacillus in
grape-sugar, agar, and in bouillon "in vaciw." His
results need confirmation. Very few instances are re-
corded in which actual inoculation has produced leprosy
in either men or animals. Arning was able to secure
permission to experiment upon a condemned criminal in
the Sandwich Islands. The man was of a family entirely
free from disease. Arning introduced beneath his skin
fragments of tissue freshly excised from a lepra nodule,
and kept the man under observation. In the course of
some months typical lesions began to develop at the
points of inoculation and spread gradually, ending in
general lepra in the course of about five years.
Melcher and Artmann introduced fragments of lepra
nodules into the anterior chambers of the eyes of rabbits,
and observed the death of the animals after some months