BACILLUS TUBERCULOSIS. 269 



field mice died, also one marmot. Fowls were in part By subcutane- 

 susceptible ; white mice were almost altogether insus- tkm! 

 ceptible. A second mode of infection was the inocula- By inoculation 

 tlon of the pure cultivations into the anterior chamber of ^eriorcham- 

 the eye in rabbits. An incision several millimetres in ber of the e y e - 

 length was made at the upper border of the cornea, and, 

 by means of a blunt hook, a minute fragment of a pure 

 cultivation was pushed into the anterior chamber, or a 

 mixture of the cultivation in water was injected by 

 means of a syringe which possessed a fine, sharp 

 canula. If by this mode of infection few bacilli were 

 injected, tuberculosis of the iris occurred somewhat 

 more quickly than after the introduction of tubercular 

 tissue. This was followed by swelling and caseation of 

 the nearest lymphatic glands, and subsequently by 

 tubercular infection of other organs. Where large 

 quantities of bacilli were injected, however, caseation of 

 the bulb and general tuberculosis rapidly occurred, so 

 that the lymphatic glands were, as it were, passed over 

 by the infection. 



In a third series of experiments, a mixture of the By injection 

 cultivations was injected into the peritoneal cavity. By Abdominal 

 this mode of infection, animals which were otherwise cavit y- 

 very insusceptible to the disease such as dogs, rats, and 

 white mice died with extensive eruption of tubercles 

 in the abdominal organs. Fourthly, mixtures of the By intra- 

 cultivations, which had been filtered through fine Ejection, 

 gauze, were injected into the veins (the jugular or 

 aural vein). By this method the most rapid and most 

 complete infection was obtained, an enormous number 

 of tubercular nodules appearing in a much shorter time 

 than is ever the case in spontaneous tuberculosis. In 

 these experiments, therefore, the possibility of spon- 

 taneous tuberculosis can be excluded most readily, and 

 with the greatest certainty. 



Lastly, Koch attempted to introduce the cultivations By inhalation, 

 of bacilli into the animals by inhalation. The mixture of 

 the cultivations with water was sprayed by means of a 

 hand spray into the interior of a box standing in the 

 open air, and in this box 20 to 30 rabbits, guinea-pigs, 



