EINDEEPEST. 379 



an invasion is attended with difficnlties. Certain appearances which 

 are characteristic of one epizootic may be absent in another. Dif- 

 ferent observers are not quite agreed as to the most constant and 

 important. 



The period of incubation, i. e., the time between the exposure to 

 infection and the earliest outward symptoms, varies from three to 

 nine days. The first sign is a very high fever, which may reacli 

 107° F. The heat of the skin varies in different parts of the body, 

 and may be felt at the base of the ears and horns. Repeated chills 

 are frequently observed. The pulse reaches 50 to 60 beats a minute, 

 and in very severe attacks may rise to 90 or 100. 



The animal manifests great debility. The head droops and rests 

 on some object of support. One or both ears may droop. The coat 

 is staring and the muzzle dry. The secretion of milk diminishes 

 very rapidljr. Within twelve to twenty hours the usual quantity 

 may have become reduced one-half or two-thirds. The back is 

 arched, and the four limbs are brought together under the body. 



As the disease progresses, syinptoms with reference to the diges- 

 tive and respiratory organs become prominent. The mucous mem- 

 brane of the mouth and the nose, as well as that of the rectum and 

 vagina, becomes reddened, either in patches or diffusely, and assumes 

 a scarlet hue. The discharges, at first firm, become softer, and soon 

 diarrhea sets in. This is said to be one of the most constant symp- 

 toms. The rectum may become everted and paralyzed, and the 

 bowels mo^^e spontaneoush'. The discharges become fetid, viscid, 

 and streaked with blood. Coughing is a common sj-mptom, and 

 by some is considered characteristic. It is associated with dis- 

 charges from the nose and vagina and dribbling of saliva from the 

 mouth. The eyes also are affected. There is an increased forma- 

 tion of a viscid secretion which flows down the face. 



Another series of changes prominent in some epizootics and mild 

 or absent in others are the ulcers, or so-called " erosions," in the 

 mouth. These begin as red patches and streaks. The mucous mem- 

 brane in such localities is converted into a grayish-white slough, 

 which, when shed, leaves a small erosion, or ulcer. At the same 

 time similar changes may go on in the skin of the thighs, the udder, 

 or the scrotum, or about the vagina, which lead to small sloughs. 



In severe cases, which are the most common in the susceptible 

 cattle of \^'estern Europe, death ensues four to seven days after 

 the first appearance of the disease, and is preceded by great ema- 

 ciation and debility, fetid, purulent discharges from the nose and 

 mouth, and the relaxed rectum and vagina. 



After death, if the animal is opened and the organs carefully 

 examined, the chief changes are found in the digesti\e organs. The 

 lining membrane of the mouth and pharynx is covered with mucus, 



