342 



AIICRO-ORGANISMS AND DISEASE [chap. 



ciice in the intensity and duration of the process is decidedly 

 more pronounced with bovine than human tubercular matter, 

 and also in the rabbit the difference between feeding with 

 bovine and with human tubercular matter is striking; so 

 that there can be no question that bovine tubercular 

 matter acts in a conspicuous degree more virulently than 

 human tubercular matter, both in guinea-pigs and rabbits. 



Fig. 133. — A sixglf, Gi.^nt-cei.l in Bovine Pulmonary Tl-cickci.e containing 



NLiMEKOUS TUI'.ERCLE BACILLI ; AROUND THE.M THE CHARACTERISTIC RiNG OF 



THE Nuclei. (A. Pri.ngle.) 



Feeding calves with milk derived from an udder con- 

 taining tubercular deposits produced tuberculosis in these 

 calves, but milk coming from a healthy udder (though the 

 cow had tubercles in the lung) failed to produce tubercle. 



Hirschberger {E.xpcrim. Beitnige ziif Inf. dcr Milch ttihcr- 

 culoser Thiere, Miinchen, 1SS9) finds that at least five per 



