496 GrE^'EEAL DISEASES. 



COURSE. — Before the invention of mallein (p. 614), glanders 

 was recognised only by its outward symptoms, and it was regarded 

 as a very severe and nearly always an incurable disease. Instances 

 have occurred of horses with outward signs of glanders (p. 500), and 

 especially of farcy, having apparently recovered. " When the mallein 

 test is applied to a large stud of horses among which glanders has 

 existed for several years, it frequently happens that a notable pro- 

 portion of the animals react — perhaps 20 per cent, or more — al- 

 though for a number of years previously, the proportion of animals 

 which have developed symptoms of the disease, may have been very 

 much smaller than that. It is this experience which justifies the 

 view that, apart from any curative effect of mallein, many cases of 

 glanders run a mild course, and ultimately end in complete re- 

 covery " (BIcFadyean). 



The microbes of glanders are taken up by the blood-vessels, what- 

 ever their port of entrance into the body may have been, and their 

 presence in various tissues causes the formation of nodules 

 (tubercles) which may become converted into abscesses and 

 ulcers. The lymphatic vessels of an affected part become 

 filled with virulent material (their office being to remove waste 

 products), and consequently they become inflamed. The form 

 taken by the disease depends on the part in which nodules appear, 

 as, for instance, the lungs and air passages in glanders; and the 

 skin in farcy. 



The apparent reason for the submaxillary glands (the glands 

 between the branches of the lower jaw) becoming affected, when 

 ulcers form inside the nostrils, is that they receive the lymphatic 

 vessels of the nasal cavities, and consequently become inflamed 

 by the microbes which are brought to them by these vessels. The 

 rise of temperature is due to the heat-producing products (p. 449) 

 manufactured by the microbes of this disease. 



When recovery sets in, the tubercles dry up, harden, and become 

 respectively enclosed by tissue which forms capsules round them. 

 The encysted colonies of bacilli thus gradually lose their power 

 of transmitting the disease, and finally die. 



It is generally thought that the lungs are almost always the first 

 organ attacked by the bacilli of glanders, because, on 'post-niortem 

 examination, they usually manifest the presence of grey translucent 

 nodules which have a tendency to calcify (to become more or less 

 turned into lime). Professor Schiitz (" Journal of Comp. Path.," 

 March, 1898) maintains that these grey translucent nodules have 

 no connection with glanders, but are the result of minute thread- 

 worms blocking up small blood-vessels in the lungs, and thereby 

 setting up inflammation, with consequent formation of tubercles. 

 He says " that in spite of a most extensive experience, I have not 



