DISEASES OF HORSE* 67. 



of anthrax and retain their vitality throughout months of soaking 

 in the tanners' pits, the working of the harness maker or the cob- 

 bler, and after the oiling of the completed leather. The dried spores 

 in the dust from any of these products may be carried by the atmos- 

 phere. 



Infection of an animal takes place through inoculation or con- 

 tact of the bacillus or its spores with an abraded surface or mucous 

 membrane on a sound animal. In an infected district horses may 

 eat the rich pasturage of spring and early summer with impunity, 

 but when grass become low they crop it close to the ground, pull up 

 the roots around which the virus may be lodged, and under these 

 conditions the animals are more apt to have abrasions of the lips 

 or tongue by contact with dried stubble and the dirt on the roots, 

 which favors the introduction of the germs into the system. The 

 virus may be introduced with food and enter the blood-vessel system 

 from the stomach and intestines. If contained in the dust, dried 

 hay, or on the parched pasture of late summer, the virus may be 

 inhaled and be absorbed from the lining of the lungs. If contained 

 in harness leather, it needs but an abrasion of the skin, as the har- 

 ness rubs it, to transfer the spore from the leather to the circulation 

 of the animal. 



Symptoms. The symptoms of anthrax usually develop with 

 extreme rapidity. The horse is dejected and falls into a state of pro- 

 found stupor, attended by great muscular weakness. The feeble, 

 indolent animal, if forced to move, drags its legs. There are severe 

 chills, agitation of the muscles, symptoms of vertigo, and at times 

 colicky pains. The mucous membranes turn a deep ocher or bluish 

 red color. The body temperature is rapidly elevated to 104 or 

 105 F. The breathing is increased to thirty or forty respirations 

 in the minute and the pulse is greatly accelerated, but while the 

 arteries are soft and almost imperceptible, the heart beats can be felt 

 and heard, violent and tumultuous. In some cases, when inoculation 

 is through the skin, large subcutaneous swellings appear; these mav 

 involve a leg, a shoulder, one side of the body, or the neck or heacL 

 The swelling is at first hot and painful, but afterwards it becomes 

 necrotic and sensation is lost. The symptoms last but two, three, 

 or four days at most, when the case usually terminates fatally. 



Treatment. The treatment of anthrax has little in it to en- 

 courage one. The curative treatment, for which almost every drug 

 in the pharmacopoeia has been used, is practically without avail. 

 The treatment formerly consisted in the avoidance of certain fields 

 and marshes which were recognized as contaminated during the 

 months of August and September and had been occupied the years 

 in which the outbreaks usually occurred. It underwent, however, 

 a revolution after the discovery of the possibility of a prophylactic 

 inoculation or vaccination which granted immunity from future 

 attacks of the disease similar to that granted by the recovery of an 

 animal from an ordinary attack of the disease. 



This treatment consists in the use of a vaccine which is made 

 by the artificial cultivation of the virus of anthrax in broth and in 



