^ETIOLOGY OF TUBERCULOSIS. 
117 
1.—Perlsuoht of Cattle. 
The tuberculosis of cattle runs its course, as is well known, almost always 
by the forming of little knots which do not really become caseous and perish, 
but become calcareous and heap themselves together in such masses that they 
can finally form great tumors. But beside these there occur widespread firmly 
caseous infiltrations of the lung tissue, as well as hollow spaces in the lungs, 
filled with pap-like caseous masses. 
Of the last mentioned form only four cases were examined. The caseous 
contents of the cavities were of such a consistence that when the cavities were 
cut the contents could be pressed out in sausage-shaped masses. The cavities 
themselves appeared to have proceeded from enlarged broncliiae. In their 
walls were found quite numerous giant cells, and in a number of these last 
one to several tuberculous bacilli. The caseous masses were, as the inoculations 
performed with them showed, infectious, yet no bacilli could be found in them. 
On the places where the “ bronchi-ectatischen ” cavities approached the 
surface of the lungs, the usual knot-shaped tumors of the “ perlsucht ” were 
found on the pleura, and showed the immediate connection with this form of 
cattle tuberculosis. 
Of this last form eleven cases were examined in which the development of 
the knots of the “ perlsucht” did not confine themselves to the lungs, but 
reached out to the diaphragm, peritoneum and omentum. Several times the 
mesenterial glands were tuberculously changed and impregnated with firm 
caseous herds. The tuberculous bacilli were wanting in no case, yet here 
their number was extraordinarily fluctuating. In some cases only comparatively 
few bacilli, and those exclusively in the giant cells of the “perlsucht” knots, 
were found, similarly as in scrofulous glands, and in the already mentioned 
caseous (cheesy) herds in the lungs of cattle. I am, therefore, not able to share 
the often-expressed opinion that “ perlsucht ” knots, in contract with the tub¬ 
ercles in man, are always rich in bacilli. Besides such cases as run their 
course slowly and always show very few bacilli, there are those in which 
permanently or only temporarily the number of bacilli may be very consider¬ 
able. 
Also, in the same lung bacilli may be found to be very numerous in some 
spots and very scarce in others. Sections prepared from large and hard, 
therefore older knots contained often only scattered bacilli in giant cells. 
The younger knots, on the contrary, showed themselves extraordinarily rich 
in bacilli and allowed the recognition of the formerly mentioned relations 
between bacilli and giant cells with great ease. 
Besides this, bacilli are found between the small cells in snch numbers 
that in places they give the specimen a bluish color. 
The caseous mesentric glands of cattle suffering from “perlsucht”, which 
I received for examination, were always extraordinarily rich in bacilli. The 
bacilli were, on the contrary, less numerous in the ragged “ perlsiichtigen ” 
luxuriant growths, permeated with many little hard knots and taken from the 
pericardium of a beef-creature and also in the knots, which in such a case had 
their seat in the kidneys. In all the number of cases of “ perlsucht ” examined 
amounted to seventeen, and the bacilli were wanting iu none of them. 
