334 MICRO-ORGANISMS AND DISEASE [chaP. 



human and bovine, produced disseminated tuberculosis. 

 The tubercular deposits of all such experimental animals 

 transferred to normal animals again produced the same 

 tuberculosis. 



When inoculation into the subcutaneous tissue of the 

 groin of guinea-pigs is carried out with a minute particle of 

 human tubercular material, after a lapse of about twelve 

 days, more or less, the lymph gland nearest the seat of 

 inoculation can be easily felt, being a firm swollen nodule 

 of the size of a pea ; after a lapse of a further ten or twelve 

 days the first gland is much enlarged (size of a bean or 

 filbert) and may have become already changed into an 

 abscess firmly fixed to the skin, but one or the other lymph 

 gland near it can now be felt as a firm swollen nodule. The 

 abscess soon opens and discharges thick creamy pus, a sore 

 is established which persists, and though it may from time 

 to time become covered with scab or crust, the accumula- 

 tion of thick pus underneath soon causes again its being 

 opened. The other enlarged lymph glands about the 

 seat of inoculation also become converted into abscesses. 

 When killing the animal after about four to six weeks, we find 

 at the seat of inoculation an open sore discharging thick pus, 

 and the subcutaneous connective tissue around and for some 

 distance is hyperaemic and oedematous. In connection with 

 the sore we find a chain or a packet of swollen firm lymph 

 glands (from the size of a split pea to that of a bean) con- 

 taining cheesy, yellow deposits. When cutting into such a 

 gland we find it very juicy, and containing larger or smaller 

 yellowish masses ; in the largest gland some of these masses 

 are already changed into thick creamy pus. At or about 

 this stage, i.e. four to six we^ks, in most instances either no 

 tubercles visible to the unaided eye are yet found in the 

 lungs, or only very few minute punctiform nodules ; in the 



