426 LETTER TO THE "TIMES." 



five days the remaining five were killed and examined. 

 In the guinea-pig that died, and in the three remain- 

 ing infected ones, strongly-pronounced tubercular dis- 

 ease had set in. Spleen, liver, and lungs were found 

 filled with tubercles; while in the two uninfected ani- 

 mals no trace of the disease was observed. In a 

 second experiment, six out of eight guinea-pigs 

 were inoculated with cultivated bacilli, derived origi- 

 nally from the tuberculous lung of a monkey, bred 

 and re-bred for ninety-five days, until eight gen- 

 erations had been produced. Every one of these ani- 

 mals was attacked, while the two uninfected guinea-pigs 

 remained perfectly healthy. Similar experiments 

 were made with cats, rabbits, rats, mice, and other ani- 

 mals, and, without exception, it was found that the 

 injection of the parasite into the animal system was 

 followed by decided and, in most cases, virulent tuber- 

 cular disease. 



In the cases thus far mentioned inoculation had 

 been effected in the abdomen. The place of inoculation 

 was afterwards changed to the aqueous humour of the 

 eye. Three rabbits received each a speck of bacillus- 

 culture, derived originally from a human lung affected 

 with phthisis. Eighty-nine days had been devoted to 

 the culture of the organism. The infected rabbits rap- 

 idly lost flesh, and after twenty-five days were killed 

 and examined. The lungs of every one of them were 

 found charged with tubercles. Of three other rab- 

 bits, one received an injection of pure blood-serum 

 in the aqueous humour of the eye, while the 

 other two were infected in a similar way, with the 

 same serum, containing bacilli derived originally 

 from a diseased lung, and subjected to ninety-one 

 days' cultivation. After twenty-eight days the rabbits 

 were killed. The one which had received an injec- 



