SYSTEMATIC AND DESCRIPTIVE. 275 



of man, monkeys, cattle (Perhuchf), 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. 107). 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. 

 Morphologically identical bacilli have also been 

 observed, but very sparsely, in sections of lupus. 



METHODS OF STAINING THE TUBERCLE BACILLUS. 



Numerous methods have been recommended for staining 

 the bacillus tuberculosis, each of which will be given in detail 



Ehrlichs and Gibbes 1 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 EhrlicJis and Neehens 

 methods give excellent results. 



Koctis 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. 



