AETIOLOGY OF TUBERCULOSIS. 
163 
only a secondary part. This question could only be decided by inoculating the 
bacilli perfectly pure and separate from all parts of the body. If they then also 
created tuberculosis, they must be the only and indisputable infectious material of 
tuberculosis. The high importance which belong to just this part of the investi¬ 
gation demanded that the strictest prudential measures should be taken to exclude 
all errors. With regard to this, as in the former attempts, for every single exper¬ 
iment several freshly bought animals were used. Besides this special counter¬ 
acting attempts went along with most of the attempts. The animals of every 
experiment were in a special cage and were strictly separated from all other tuber¬ 
culous ones ; they were also killed as early as possible to prevent a collision with 
spontaneous tuberculosis and any objection arising therefrom. Further, as various 
methods of infection as possible and as various species of animals were used in 
order to find out the working of the reinculturen in this direction. The greatest 
care was used in the disinfection of all the vessels and instruments used, especially 
the syringes. The culturen serving for infection consisted (as was specially 
proved almost every time), wholly of tuberculous bacilli. The same were lifted 
with all caution by means of platinum wires heated until red from the stiffened 
blood serum, which, as has already been expressly mentioned, can easily be done 
without tearing off the least bit of the blood serum. It is therefore not too much 
to claim that in most of the attempts absolutely pure bacilli masses were used to 
which nothing of the breeding ground on which they grew clung. Moreover, in 
several attempts sterilized blood serum was injected into the animals, which 
served for the counteracting attempts without the appearance of a trace of tuber¬ 
culosis. One can therefore claim with all certainty that when genuine tuberculosis 
is caused by the infection with a tuberculous bacilli-reincultur, which has been 
continued through several successive breedings, this is to be ascribed alone to the 
effect of the tuberculous bacilli. 
First experiment: Reincultur of miliary tubercles of the human lung (No. 
22 in the former enumeration of the reinculturen) cultivated through five suc¬ 
cessive breedings for fifty-four days, subcutaneously inoculated into four guinea 
pigs. Two animals in the same cage were not inoculated. In the inoculated 
animals after forteen days the inguinal glands swelled, the places of inoculation 
changed into abscesses and the animals began to grow emaciated. One of them 
died after thirty-two days, the others were killed on the thirty-fifth day. The 
inoculated guinea pigs, as well the one which died as the three which were killed, 
showed tuberculosis of the spleen, liver and lungs to a high degree ; the inguinal 
glands were greatly swollen and caseous, and, moreover, decidedly more so on 
the inoculated side; the bronchial glands were little swelled. The two uninocu¬ 
lated animals showed no trace of tuberculosis. 
Second experiment: Reincultur from the tuberculous lung of a monkey, 
(No. 11) cultivated ninety-five days in eight successive breedings, inoculated sub¬ 
cutaneously into six guinea pigs. Two animals for counter-experiment remained 
uninoculated. All the animals were killed after thirty-two days and the six in¬ 
oculated were found tuberculous to a high degree, the two others healthy. 
Third experiment: Reincultur from a perlsucht lung (No. 37) cultivated for 
seventy-two days through six successive breedings, subcutaneously inoculated 
into five guinea pigs; one animal remained uninoculated. When the animals 
