DISEASES OF CATTLE 313 



spite of the foregoing statements the consensus of opinion of eminent 

 investigators points to malignant catarrh as being of specific origin ; 

 that is, due to some form of micro-organism the contagious character 

 of which is poorly developed. This accounts for the slow transmissi- 

 bility of the disease from one animal to another. In fact, malignant 

 catarrh is a type of that class of affections which are scientifically 

 known as misasmatic diseases; that is, they remain stationary in sta- 

 bles with damp floors, low ceilings, poor ventilation, and bad sanitary 

 conditions in general. Such places furnish a favorable seat of propa- 

 gation for the infective material, and it will remain active for a long 

 period of time, causing the loss of a few animals each year. One Eu- 

 ropean veterinarian reports an instance where this disease remained 

 for twenty-five years on the same farm, attacking in all 225 animals, 

 with a mortality of about 98 per cent. 



The disease is most common in late winter and early spring, at 

 all altitudes, and has a special preference for young, well-nourished 

 cattle, although older animals are not immune. The time elapsing 

 between the entrance of the infective principle into the body of the 

 animal and the appearance of the first symptoms is relatively very 

 long and, according to German investigators, averages from twenty to 

 thirty days. Fortunately, it is not a disease which spreads to any 

 great extent, or which causes severe losses, and hence legislative en- 

 actments do not seem to be necessary for its restriction. 



Symptoms. These are extremely variable according to the point 

 of localization of the lesions. It is usually ushered in with a chill, 

 followed by a marked rise of temperature (104 to 107 F.). The 

 head droops, the skin is hot and dry, and the coat staring. Quiver- 

 ing of the muscles in various parts of the body is frequently ob- 

 served. Marked dullness of the animal passing, according to some 

 observers, into an almost stupefied condition later on, is quite com- 

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

 and loss of flesh, invariably associated with the disease, is extremely 

 marked and rapid. The lesions of the eyes may best be likened to 

 moon blindness (periodic ophthalmia) in horses. 



There is first an abundant secretion of tears, which run down 

 over the face. The lids are swollen and inflamed, and indeed this 

 may be so marked as to cause involuntary eversion, exposing the red- 

 dened conjunctiva to view. Sunlight is painful, as is shown by the 

 fact that the animal keeps the eyes continuously closed. This inflam- 

 mation may extend to the cornea, causing it to assume a slight 

 clouded appearance in mild cases or a chalky whiteness in more severe 

 affections. Cases of ulceration of the cornea followed by perforation 

 and subsequent escape of the aqueous humor, leading to shrinking of 

 the eyeball and permanent loss of sight, have been recorded; but 

 these are relatively rare, although slight inflammation of the deeper 

 structures of the eye (iris) are more frequent. This inflammation 

 may undergo complete resolution in mild cases, but more frequently 

 permanent cloudiness of the cornea either diffuse or in spots 

 (leucoma) is the result. The mucous membrane of the mouth, nose, 

 sinuses of the head, throat, and lower respiratory passages are also 



