PATHOLOGICAL RESULTS, ETC. 339 



found infective only when the udder was the seat of tuber- 

 culosis, and was highly infective in those cases in which 

 tubercle bacilli were readily discoverable by microscopical 

 examination, but was less infective when the bacilli were 

 with difficulty found, or were not found at all, although the 

 results of experiment showed that they were present. 



If a large dose of tuberculous material, bovine or human, 

 is introduced under the skin of the groin of the guinea-pig, 

 a local lesion is produced in from seven to ten days, and a 

 subsequent infection of the inguinal glands occurs ; in four- 

 teen to twenty clays an affection of the lumbar and cceliac 

 glands, followed by a spread of the disease to the posterior 

 mediastinal and bronchial glands, and to the lungs ; this 

 occurs in about the fourth or fifth week. Subsequently the 

 cervical glands, the anterior mediastinal, and even the 

 mesenteric glands may be affected ; while the liver and 

 spleen are affected in about the same time as the cceliac 

 glands, that is, in about three weeks. There is, therefore, 

 after inoculation in the guinea-pig, a gradual spread of the 

 disease along the lymphatic channels ; from inoculation, a 

 local lesion of the mucous membrane of the intestine never 

 results. This rapid spread of the disease is, however, not 

 seen in some cases of inoculation with meat and milk, in 

 which the infectivity is slight. In these cases — several of 

 which were observed — even when the animal was inoculated 

 in both groins, tuberculosis developed on one side only ; 

 also in some instances the disease remained quite localised. 

 In one guinea-pig, for example, inoculated in each groin 

 with meat, and dying in sixty-two days, the right inguinal 

 region was normal, but in the left inguinal region a small 

 scar was found inside the nipple, which, on microscopical 

 examination, showed a structure closely resembling that of 

 lupus, and the presence of a small number of tubercle 

 bacilli. No other gland or organ of the body was affected 

 by the disease. Similar localisation of the disease to the 

 inguinal region was found in three other experiments in 

 rabbits inoculated with meat or meat juice and killed in 66, 

 85, and 120 days after inoculation. The lesions were tuber- 

 cular, as shown by their structure and the presence of 



