No. 6. DEPARTMENT OF AGRICULTURE. 123 



The mesentery of the large as well as small intestine contains in- 

 numerable pearly nodules. The mesenteric glands are normal in 

 size and appearance. Along the abdominal aorta and brim of the 

 pelvis are twelve to fifteen glands from 5 mm. to 15 mm, in diameter, 

 vellow in color, but nooe caseous. 



The liver is adherent to the diaphragm. On the surface, as well 

 as on section, many yellowish nodules can be seen. 



The spleen is thicker than normal and very firm. On the surface 

 a few fibrous new-growths are seen. 



The kidneys appear normal, but each has a layer of the peritoneum 

 attached to it, which contains innumerable gray nodules, averaging 

 1 mm. in diameter. 



Microscopic Examination. — Lung not examined. The liver con- 

 tained many minute areas of necrosis. The kidneys contain a con- 

 siderable number of minute tubercles, with central necrosis, situated 

 for the most part immediately under the capsule. 



Another animal was inoculated in the same manner with the 

 tissues of this calf, which is still living.* Guinea-pigs have also 

 been inoculated in order to recover a pure culture, so that any 

 changes that have taken place may be studied. We feel, however, 

 that we have demonstrated a great increase in virulence in this cul- 

 ture, obtained from sputum, by the several passages through calves. 



Our own experiments, as well as those quoted from others, demon- 

 strate that Koch's statement that human tuberculosis cannot be 

 transmitted to cattle is erroneous and untenable. 



II. In the second proposition Professor Koch calls in question the 

 possibility of the transmission of tuberculosis from cattle to man, 

 and holds that if such transmission ever does take place it is a very 

 rare occurrence, so rare, indeed, as to render superfluous any meas- 

 ures of precaution against it. 



In the solution of the problems here involved we are of necessity 

 deprived of experimental data, so must gather evidence from every 

 possible source, collate and weigh it carefully, in order to draw fair 

 conclusions. 



In the first place, we niay well ask if tuberculosis in cattle is 

 marked by any specific features which diff'erentiate it from tuber- 

 culosis in man, and which would make it improbable that the two 

 were intercommunicable. I will not attempt here to go into a dis- 

 cussion of all the forms of bovine tuberculosis or to compare it- 

 minutely with the disease in man. The chief differences are: (1) 

 The marked tendency to calcification rather than the caseation seen 

 in man; (2j the formation of extensive new-growths in the serous 

 membranes, such as the pleurae and peritooeum. 



•This calf, No. A45073, died three days after the reading of the paper, or twenty-four 

 days after inoculation. There was typical and extensive tuberculosis. 



