486 BACILLI IN CHRONIC INFECTIOUS DISEASES. 
Amann (1895) has given in the Centralblatt fiir Bakteriologie 
(Bd. xvii., page 513) a detailed account of his method for demon- 
strating the presence of tubercle bacilli in sputum by sedimentation. 
He mixes the sputum with two to four volumes of cold distilled 
water, in a glass cylinder which should not be more than half full. 
He adds one cubic centimetre of chloroform and a small quantity 
of shot; the glass cylinder is then closed with a rubber cork and vio- 
lently shaken for some minutes. From four to six volumes of dis- 
Fig. 120.—Section of a recent lepra nodule of theskin, x 950. (Baumgarten.) 
tilled water are then added and the mixture is placed in a V-formed 
glass tube for sedimentation; two cubic centimetres of carbol-fuchsin 
solution are added and distributed by gentle agitation of the tube. 
At the end of two days the sedimentation is complete and the stained 
bacilli, cells, connective-tissue fibres, etc., are taken up with a pipette 
for examination under the microscope. 
BACILLUS LEPR. 
Discovered by Hansen (1879), chiefly in the interior of the peculiar 
round or oval cells found in leprous tubercles. Discovery confirmed 
by Neisser (1879) and by many subsequent observers. 
While found chiefly in the leprous tubercles of the skin and mucous 
membranes, the bacilli have also been foundin the lymphatic glands, 
the liver, the spleen, the testicles, and, in the anzesthetic form of the 
disease, in the thickened portions of nerves involved in the leprous 
process. Some observers have also reported finding them in the 
blood, but this appears to be quite exceptional. In the leprous cells 
they are commonly found in great numbers, and they may also be 
seen in the lymph spaces outside of these cells. They are not found 
in the epidermal layer of the skin, but, according to Babes, they may 
penetrate the hair follicles. 
Morphology.—The bacillus of leprosy resembles the tubercle ba- 
cillus in form, but is of more uniform length and not so frequently 
