^ETIOLOGY OF TUBERCULOSIS 
165 
of some of these animals was utterly prevented or only incompletely possible, 
because the still living field-mice, in spite of having abundant vegetable food, often 
gnawed their dead comrades and ate up the inner organs of the same with great 
ravenousness. Nevertheless, from each single division of this experiment some 
animals remained for examination, and it could therefore be determined that they 
all perished from a high degree of tuberculosis of the lungs, liver and spleen. A 
distinction in the conduct of the tuberculosis proceeding from the various rein- 
culturen was not to be recognized. The general appearance of the pathological 
changes was identical in all animals and so was the appearance of the single lit¬ 
tle knots to the naked eye, as well as their microscopic conduct and especially 
their tuberculous bacilli contents. For this experiment it is worthy of notice 
that the animals had been in imprisonment only a few days when they were in¬ 
oculated, and that a large number of other field-mice under the same conditions 
had been kept in glasses for months without a single one of them becoming tuber¬ 
culous. 
Seventh experiment: Since field-mice are such a sure and convenient re¬ 
agent for tuberculosis, for the purpose of experiments which I made with Dr. 
Gaffky twenty-four field-mice were subcutaneously inoculated with the reincul- 
tur from a phthisic lung (No. 1) cultivated for seven months in twelve successive 
breedings. These experiments were made in regard to the influence upon tuber¬ 
culous animals of substances hindering the development. Also from these aiv- 
mals, which were treated with inhalations of easily evaporating substances, some 
died after a few days of pneumonia, tuberculosis developed itself in all the 
other, and ran its course in the same way as in the mice of the previous experi¬ 
ment. Under dissection, a well-marked tuberculosis of the lungs, spleen and 
liver always showed itself. 
Eighth experiment : For the same purpose five guinea pigs were inoculated 
with reincultur from caseous pneumonia (No. 28) cultivated for six months in 
eight successive breedings; further, four guinea pigs with reincultur from a 
phthisic lung (No. 24) cultivated for six months in ten successive breedings, and 
six guinea pigs with reincultur from tuberculosis of the testicles (No. 83) culti¬ 
vated for three months in five successive breedings—all subcutaneously. These 
animals had also various gas-like development-hindering substances to breathe 
in, but in spite of it became sick and emaciated, died within four to six weeks 
and were under dissection all found tuberculous. 
Ninth experiment: Reincultur of lupus (No. 35) cultivated for twelve 
months in fifteen successive breedings subcutaneously inoculated into five guinea 
pigs. This experiment was undertaken in order to see whether the continuation 
of the cultur of tuberculous bacilli from lupus-skin for the space of a whole year 
had any influence upon the virulence of the same. This was, neverthless, not 
the case. The inoculated animals were taken sick just as surely and quickly as 
in the former experiments; two died in the fourth week, the others were then 
killed and all found under dissection to be tuberculous in a high degree. 
Tenth experiment: With the same intention the longest continued reincul¬ 
tur (No. 1) of human lung phthisis, cultivated for eighteen months iu twenty-six 
successive breedings, was subcutaneously inoculated into four guinea pigs. The 
course of the disease was just the same as in the ninth experiment. The animals 
died in the fourth and fifth week of the inoculation and were tuberculous. 
