r 
1891.] ` Editorial. 123 
Pasteur; nor is there any doubt as to the claims of Professor 
Koch to the discovery of the tubercle bacillus. 
In the month of March, 1882, Dr. Koch announced to the 
medical world that he had discovered the existence of a microbe 
hitherto unknown, and to which was given the name of the tuber- 
cle bacillus. He described how he had subjected diseased or- 
gans of numbers of men and animals to microscopic examination, 
and found, in all cases, the tubercles infested with a minute, rod- 
shaped parasite, which, by means of a special staining process, he 
differentiated from the surrounding tissue. He says: “ It was in 
the highest degree impressive to observe in the center of the 
tubercle cell the minute organism which had created it.” 
Professor Klein differs from this view. He says: “I cannot 
agree with Koch, Watson Cheyne, and others, who maintain that 
each tubercle owes its origin to the immigration of the bacilli, for 
there is no difficulty in ascertaining that, in human tuberculosis, 
in tuberculosis of cattle, and in artificially induced tuberculosis of 
guinea-pigs and rabbits, there are met with tubercles in various 
stages, young and old, in which no trace of a bacillus is to be 
found, whereas in the same section caseous tubercle may be 
present containing numbers of tubercle bacilli.” 
Transferring directly by inoculation the tuberculous matter 
from diseased animals to healthy ones he in every instance re- 
produced the disease. To meet the objection that it was not the 
parasite itself, but some virus in which it was embedded, he cul- 
tivated his bacilli artificially for long periods of time and through 
many successive generations. 
This was confirmed by reliable investigations, and thus was 
established the existence of the tubercle bacillus and its discovery 
by him, and up to this time everything is plain sailing. 
From the date of this announcement (1882) by Professor Koch, 
up till October, 1889, nothing particularly new was heard on the 
subject, and as far as the literature on the tubercle bacillus goes, 
_ we have every reason to believe that the search for a toxic agent 
to combat the disease of tuberculosis and the ravages of the 
tubercle bacillus has been fruitless. Indeed, to all outside appear- 
ances, the tubercle bacillus, having been once discovered, was to 
d 
