EXPERIMENTAL INOCULATION. 247 



swelling forms, which soon softens and breaks down, leading 

 to the formation of an irregular crateriform ulcer with 

 indurated margins. The lymphatic vessels become in- 

 filtrated, and the corresponding lymphatic glands become 

 enlarged to the size of peas or small nuts, softened, and 

 semi-purulent. The animal sometimes dies in two or three 

 weeks, sometimes not for several weeks. Secondary 

 nodules, in varying numbers in different cases, may be 

 found in the spleen, lungs, bones, nasal mucous membrane, 

 testicles, ovaries, etc. ; in some cases a few nodules are 

 found in the spleen alone. Intraperitoneal injection in 

 the male guinea-pig is followed, as pointed out by Straus, 

 by a very rapid and semi-purulent affection of the tunica 

 vaginalis, shown during life by a great swelling and redness 

 of the testicles, which may be noticeable in two or three 

 days. By this method there occur also extensive deposits 

 in the omentum, and numerous small nodules on the 

 surface of the peritoneum. Minute nodules may be present 

 in the various organs, but they are often invisible to the 

 naked eye. 



Rabbits are less susceptible than guinea-pigs, and the 

 effect of subcutaneous inoculation is somewhat uncertain. 

 Sometimes only a local lesion results, sometimes a general- 

 ised affection. 



Action on the Tissues. From the above facts it will be 

 seen that in many respects glanders presents an analogy 

 to tubercle as regards the general characters of the lesions 

 and the mode of spread. In the guinea-pig, for example, 

 there are in both diseases a local swelling, an implication 

 of lymphatics in connection with the part, and, lastly, a 

 spread to internal organs and other parts by means of 

 the blood vessels. When the tissue changes in the two 

 diseases are compared, certain differences are found. The 

 glanders bacillus causes a more rapid and more marked 

 inflammatory reaction. There is more leucocytic infiltra- 

 tion and less proliferative change which might lead to 

 the formation of epithelioid cells. Thus the centre of 

 an early glanders nodule shows a dense aggregation of 



