TUBERCULOSIS. 387 



tion of a recent tubercle in blood-serum or distilled 

 water, they may be recognized with a suitable 

 objective and illuminating apparatus, without the 

 use of staining reagents. An examination made 

 under these circumstances shows that the bacilli 

 are motionless, and in some rods spores of oval 

 form may be distinguished. At the time of his 

 first report, Koch had examined in man, " Eleven 

 cases of miliary tuberculosis, twelve cases of cheesy 

 broncho-pneumonia, one case of tubercle in the 

 brain, and two cases of intestinal tuberculosis." In 

 all of these the bacilli were present. They were 

 also found in freshly extirpated scrofulous glands. 

 Among the lower animals they were found in ten 

 cases of perlsuckt, in three cases of so-called bron- 

 chiectasis in cattle ; in three monkeys, nine guinea- 

 pigs, and seven rabbits, which had spontaneous 

 tuberculosis ; and in one hundred and seventy-two 

 guinea-pigs, thirty-two rabbits, and five cats, which 

 had been inoculated with tuberculous material, or 

 with pure cultures of the bacillus. 



The gelatine culture-medium which had been 

 previously recommended by Koch was found not 

 to be suitable for the cultivation of the tubercle 

 bacillus, as the advantage of solidity is lost when 

 this is heated to 98 Fahr. Jellified blood-serum, 

 prepared as directed on page 163, was found, how- 

 ever, to fulfil all the required conditions, and was 

 used by Koch in his culture experiments. Portions 

 of tubercles removed, with proper precautions to 

 prevent contamination, from the bodies of persons 



