BACILLI IN CHRONIC INFECTIOUS DISEASES. 419 



made with milk forms an extremely favorable medium, upon which 

 a thick, pale- white layer develops in two or three days, which on the 

 third or fourth day acquires an amber-yellow color, and the deeper 

 layers acquire a brownish-red tint. 



The growth upon solidified blood serum, in the course of three or 

 four days at 37 C., consists of yellowish, transparent drops, which 

 later coalesce into a viscid layer, which has a milky appearance from 

 the presence of numerous small crystals (Baumgarten). The growth 

 upon cooked potato is especially characteristic. In the incubating 

 oven, at the end of two or three days, a rather thin, yellowish, trans- 

 parent layer develops, which resembles a thin layer of honey. Later 

 this ceases to be transparent, and the amber color changes, at the 

 end of six to eight days, to a reddish-brown color ; and outside of 

 the reddish-brown layer, with more or less irregular outlines, the 

 potato for a short distance acquires a greenish-yellow tint. 



Pathogenesis. Glanders occurs principally among horses and 

 asses, but may be contracted by man from contact with infected 

 animals ; it has also been communicated, in one instance with a fatal 

 result, by subcutaneous inoculation, resulting accidentally from the 

 use of an imperfectly sterilized hypodermic syringe which had pre- 

 viously been used for injecting cultures of the bacillus into guinea- 

 pigs. The field mouse and the guinea-pig are especially susceptible 

 to infection by experimental inoculations ; the cat and the goat may 

 be infected in the same way. Lions and tigers in menageries are 

 said to have contracted glanders from being fed upon the flesh of in- 

 fected animals (Baumgarten). Rabbits have but slight susceptibility, 

 and the same is true of sheep and dogs ; swine, cattle, white mice, 

 and common house mice are immune. 



The etiological relation of the bacillus is fully established by the 

 experiments of Loffler and Schutz, confirmed by other bacteriologists, 

 which show that pure cultures injected into horses, asses, and other 

 susceptible animals, produce genuine glanders. The disease is char- 

 acterized in the equine genus by the formation of ulcers upon the 

 nasal mucous membrane, which have irregular, thickened margins 

 and secrete a thin, virulent mucus ; the submaxillary lymphatic 

 glands become enlarged and form a tumor which is often lobulated ; 

 other lymphatic glands become inflamed, and some of them suppurate 

 and open externally, leaving deep, open ulcers ; the lungs are also 

 involved and the breathing becomes hurried and irregular. In farcy, 

 which is a more chronic form of the same disease, circumscribed 

 swellings, varying in size from a pea to a hazelnut, appear on differ- 

 ent parts of the body, especially where the skin is thinnest ; these 

 suppurate and leave angry-looking ulcers with ragged edges, from 

 which there is an abundant purulent discharge. The specific bacillus 



