468 BACILLI IN CHRONIC INFECTIOUS DISEASES. 
and advanced pathologists were quite prepared to accept it. The 
more conservative have since been obliged to yield to the experi- 
mental evidence, which has received confirmation in all parts of the 
world. To-day it is generally recognized that tuberculosis is a spe- 
cific infectious disease due to the tubercle bacillus. 
As evidence of the thorough nature of Koch’s personal researches 
in advance of his first public announcement, we give the following 
résumé of his investigations : 
In nineteen cases of miliary tuberculosis the bacilli were found in 
the tubercular nodules in every instance ; also in twenty-nine cases 
of pulmonary phthisis, in the sputum, in fresh cheesy masses, and in 
the interior of recently formed cavities; in tuberculous ulcers of the 
tongue, tuberculosis of the uterus, testicles, etc. ; in twenty-one cases 
of tuberculous—scrofulous—lymphatic glands ; in thirteen cases of 
tuberculous joints ; in ten cases of tubercular bone affections ; in four 
cases of lupus; in seventeen cases of Perlsucht in cattle. His ex- 
perimental inoculations were made upon two hundred and seventy- 
three guinea-pigs, one hundred and five rabbits, forty-four field 
mice, twenty-eight white mice, nineteen rats, thirteen cats, and upon 
dogs, pigeons, chickens, etc. Very extensive comparative researches 
were also made, which convinced him that the bacillus which he had 
been able to demonstrate in tuberculous sputum and tissues by a spe- 
cial mode of staining was not to be found in the sputa of healthy 
persons, or of those suffering from non-tubercular pulmonary affec- 
tions, or in organs and tissues involved in morbid processes of a 
different nature. 
BACILLUS TUBERCULOSIS. 
Discovered by Koch (first public announcement of discovery 
March 24th, 1882). The bacilli are found in the sputum of persons 
suffering from pulmonary or laryngeal tuberculosis, either free or in 
the interior of pus cells; ey miliary tubercles and fresh caseous 
masses, in the lungs or elgewhere ; in recent tuberculous cavities in 
the lungs ; in tuberculous glands, joints, bones, and skin affections 
(lupus) ; in the lungs of cattle suffering from pulmonary tubercu- 
losis—Perlsucht ; and in tubercular nodules generally in animals 
which are infected naturally or by experimental inoculations. 
In the giant cells of tubercular growths they have a peculiar and 
characteristic position, being found, as a rule, upon the side of the 
cell opposite to the nuclei, which are crowded together in a crescentic 
arrangement at the opposite pole of the cell. Sometimes a single 
bacillus will be found in this position, or there may be several. 
Again, numerous bacilli may be found in giant cells in which the 
nuclei are distributed around the periphery. They are more numer- 
