424 DISEASES OF CATTLE. 



have definitely proved that it is a specific disease produced by bacilli, 

 readily distinguishable from anthrax bacilli. (Plate xxix, Fig. 4.) 

 Cuttle between 6 months and 4 years of age are the most susceptible. 

 Sucking calves under 6 months are not attacked, nor are they as sus- 

 ceptible to inoculation as older animals. 



Like anthrax, black-quarter is more or less restricted to definite 

 localities. There are certain pastures upon which the disease regularly 

 appears in the summer and fall of the year. As to any peculiarities of 

 the soil nothing is definitely known. Some authors are inclined to 

 regard moist, undrained, and swampy pastures favorable to this disease. 

 It occurs in different parts of our own country. In Europe it exists in 

 France, various parts of Germany, in Belgium, Italy, in the Alps, and 

 in Algeria. 



The cause of the disease is a bacillus resembling in some respects 

 the anthrax bacillus, and differing but little from it in size. It also 

 possesses the power of forming within itself a spore. In Plate xxix, 

 Fig. 4, this is represented as an uncolored spot located in one end of 

 the rod, which is enlarged so that the rod itself appears more or less 

 club-shaped. What has already been stated, concerning the significance 

 of the spore of the anthrax bacillus applies equally well to these 

 bodies. They resist destructive agents for a considerable length of 

 time, and may still produce disease when inoculated after several years 

 of drying. This fact, may account for the occasional appearance of 

 black-quarter in stables. The dry spores are carried in the hay or other 

 feed from the field, and cause disease when eaten by the susceptible 

 animals. Several observers have found this organism in the mud of 

 swamps. By placing a little of this mud under the skin the disease 

 has been called forth. 



Since the disease may be produced by placing under the skin mate- 

 rial containing the specific bacilli and spores, it has been assumed that 

 cattle contract the disease mainly through wounds, either of the skin 

 or of the mouth, tongue, and throat. Slight wounds into which the 

 virus may find access may be caused by sharp or pointed parts of the 

 food. 



The symptoms of black-quarter are both of a general and a local 

 nature. The general symptoms are very much like those belonging to 

 other acute infectious or bacterial diseases. They begin from one to 

 three days after the infection has taken place, with loss of appetite and 

 of rumination, with dullness and debility and a high fever. The tem- 

 perature may rise to 107 F. To these maybe added lameness or stiff- 

 ness of one or more limbs, due to the tumor or swelling quite invariably 

 accompanying the disease. After a period of disease lasting from one 

 and a half to three days the affected animal almost always succumbs. 

 Death is preceded by increasing weakness, difficult breathing, and 

 occasional attacks of colic. 



The most important characteristic of this disease is the appearance 



