1 62 BACTERIOLOGY. 



of man, monkeys, cattle (Perlsucht), birds, and many 

 other animals, and in cases of artificial tuberculosis, 

 in rabbits, guinea-pigs, cats, etc. (Plate XVIII., Fig. 

 2). In man the bacillus can be detected in the tis- 

 sues, in the sputum, in the blood, and in the urine.* 

 Tuberculosis may also be produced by inhalation 

 and feeding experiments (p. 92). The channels of 

 infection in man are also most probably the 

 pulmonary or intestinal mucous membranes. The 

 possibility of inoculation of skin wounds is open to 

 doubt. The bacilli or their spores are inhaled 

 from the air, or taken in with food. As a relatively 

 high temperature is required for their growth, they 

 cannot thrive outside the animal body in cold 

 climates. 



METHODS OF STAINING THE TUBERCLE BACILLUS. 



Numerous methods have been recommended for staining 

 tlie bacillus tuberculosis, each of which will be given in detail. 



Ehrlichs and Gibbes' methods may be with advantage 

 employed in staining cover-glass preparations. Gibbes 

 rapid double stain is obviously the best to employ for 

 clinical purposes. For sections both Ehrlich's and Neelsens 

 methods give excellent results. 



Koch's original method. Cover-glass preparations or 

 sections are laid in Koch's solution (No. 23, c.) for twenty- 

 four hours, or for one hour if the solution is warmed to 

 40 C. Rinse in water ; immerse in a watery solution 

 of vesuvin for two minutes ; rinse again in water, and 

 examine ; or, after rinsing in water, treat with alcohol, 

 clove-oil, and Canada balsam. 



* Babes, Centralbl. f. d. Med. Wissensch., 1883, p. 145. 



