176 
principles of bacteriology 
IX. Summary of Important Characteristics 
A slender rod, stained by special method, resists drying 
and heating better than most of the bacteria, requires 
special methods of cultivation. Tuberculosis is the most 
widely spread disease, not only among human beings, but 
also among cattle (bovine tuberculosis), birds (avian 
tuberculosis), fish, etc. Any organ in the body may be 
involved, but the lungs are the most frequently affected 
organ. Very contagious disease, favored by unhygienic 
surroundings, requires strictest disinfection; diagnosis 
rests on finding the bacilli in sputum, urine, tissue, or 
on animal inoculation, tuberculin test and complement- 
fixation test. Produces an endotoxin, no immunity treat¬ 
ment is successful. 
