INFECTIOUS DISEASES OF CATTLE. 427 



a period of incubation of three to four weeks follows the infection before 

 outward signs of disease appear. These vary very markedly from case 

 to case, and observers differ more or less in their accounts of the disease 

 as they have found it. It usually begins with a chill, followed by high 

 fever (104 to 107 F). The head droops, the skin is hot and dry, and the 

 coat staring. Quivering of the muscles in various parts of the body is 

 frequently observed. Marked dullness passing, according to some 

 observers, into an almost stupefied condition later on, is quite common. 

 The secretion of milk stops in the beginning of the disease. 



Affections of the eyes are characteristic of this malady. Then- is an 

 abundant formation of tears, which run down over the face. The lids 

 are swollen and inflamed, and the animal shuns the light by keeping 

 them closed. This simple inflammation may be followed by an inflam- 

 mation of the cornea, which may lead to permanent clouding. Inflam- 

 mation of deeper parts of the eyes (iris) is occasionally seen. 



Inflammation of the mucous membrane of the mouth, nose, and the 

 sinuses pf the head leads to discharges from the nose and mouth. The 

 mucous membrane of the nose is reddened, and may be covered later on 

 with inflammatory deposits. The discharge is at first watery, then 

 thieker, and occasionally streaked with blood and foul smelling. The 

 inflammation of the mouth is like this and leads to much dribbling of 

 saliva. It may extend to the nasal pad and 'to the nose. Inflamma- 

 tion of the throat, with deposits of a croupousor diphtheritic character, 

 lends to diilicult breathing. Various noises are produced as the air 

 Mm > in and out, depending on the place where its passage is partly 

 obstructed by mucus and exudation. If the obstruction is great signs 

 of suffocation may appear. According to some observers the horns 

 become loosened by inflammation and may be knocked off easily by the 

 ,sy, blinded animal. 



Tlie bowels are at first constipated; later, diarrhea sets in and thedis- 

 cli;ii us become soft, offensive, and streaked with blood. Some authors 

 men I ion flic discharge of exudation in the form of membranous patches, 

 which have been observed to be to 9 feet long. The kidneys are usu- 

 ally iniiamed, the urine is passed with difficulty and pain, and contains 

 abnormal elements (albumen, casts, etc.), indicative of disease. The 

 vaginal mucous membrane may be affected in a manner similar to ttiat 

 of the mouth and nose, and occasionally abortion follows. 



In connection with these various symptoms there may be much un- 

 ea-inr>s on the part of the animal, leading in some cases to madness and 

 furious dclirum, in others to spasms and convulsions or paralysis, llapid 

 emaciation is quite invariably associated with the disease in all its 

 grades. 



Like other infectious diseases, malignant catarrh pursues a longer or 

 slimier course in accordance with the severity of the attack. In acute 

 cases death is said to take place from three to seven days after the ap- 

 pearance of symptoms. When recovery ensues it may take three or 



