CATTLE PLAGUE. 145 



grey material can be distinguished. A lew hours later (some- 

 times not till twenty-four hours) the epithelium gives way, and 

 the contents become visible ; hence results a superficial lesion, 

 which, after the removal of the material lying upon it, is scarcely 

 recognisable; it heals in a few days, leaving no cicatrix. In other 

 cases these nodules become confluent, and then give rise to an 

 excavated ulcer of considerable extent, with irregular margins, 

 which, however, usually heals quickly, leaving no cicatrix. In 

 another form of the affection the epithelium is raised in the 

 form of small vesicles, which contain either a clear or slightly 

 turbid fluid, and leave behind shallow, round excavations, with 

 smooth edges.' " 



Dr. Brauell of Dorpat, who has made very extensive observa- 

 tions on the anatomy and microscopy of the disease, says that 

 the buccal mucous membrane is usually reddened in patches of 

 greater or less extent ; these patches being in some places 

 merely deprived of epithelium, in others covered wdth layers, 

 varying in size from that of a lentil to that of a fourpenny piece. 

 These layers are of a yellow or greyish colour, and of irregular 

 form ; they project from one to two lines above the surface of 

 the reddened mucous membrane, and are so soft that they can 

 be readily stripped off with the tip of the finger. ^ The mucous 

 membrane beneath is more or less reddened by congestion of 

 the capillaries and hsemorrhage, and in some cases broken down 

 in its texture ; usually, however, it is entire. Similar alterations 

 are found at the margins of the lips and nose. In addition to 

 these changes, roundish depressions about as large as a hemp 

 seed, their bases covered with a yellowish material, were 

 observed in the mucous membrane of the lips, and sometimes 

 along with them greyish nodules, which might on superficial 

 examination be easily mistaken for vesicles or pustules. On 

 pressing these, a yellowish, semi-fluid mass could be squeezed 

 out, leaving behind one of the depressions or pits above 

 described. These were the appearances seen in animals suffering 

 from the disease naturally contracted. Those seen in inoculated 

 animals did not materially differ. On the third or fourth day 

 after inoculation there was redness of the gum around the incisor 

 teeth, and, more rarely, injection of the mucous membrane of the 

 lower lip. At these spots the membrane was covered with a 

 yellowish-white material, which could easily be stripped off, 



' Su Plate i. 

 L 



