INFECTIOUS DISEASES OP CATTLE. 443 



i 



in prolonged duration, and it may occasionally terminate in recovery 

 if the swellings are thoroughly incised and treated. 



Lesions. — These swellings appear as edemas and carbuncles. The 

 former are doughy tumors of a more or less flattish form passing grad- 

 ually into the surrounding healthy tissue. They are situated as a rule 

 beneath the skin in the fatty layer, and the skin itself is at first cf 

 healthy appearance, so that they are often overlooked, especially when 

 covered with a good coat of hair. When they are cut open they are 

 found to consist of a peculiar jelly-like mass of a yellowish color and 

 more or less stained by blood. The carbuncles are firm, hot, tender 

 swellings, which later become cool and painless and undergo mortifi- 

 cation. The edemas and carbuncles may also appear in the mouth, 

 pharynx, larynx, in the tongue, and in the rectum. 



The bodies of cattle which have died of anthrax soon lose their 

 rigidity and become bloated, because decomposition sets in very rap- 

 idly. From the mouth, nose, and anus blood-stained fluid flows in 

 small quantities. When such carcasses are opened and examined, it 

 will be found that nearly all organs are sprinkled with spots of blood 

 or extravasations of various Bizes. The spleen is enlarged from two 

 to five times, the pulp blackish and soft and occasionally disinte- 

 grated. The blood is of tarry consistency, not firmly coagulated, and 

 blackish in color. In the abdomen, the thoracic cavity, and in the 

 pericardium, or bag surrounding the heart, more or less blood-stained 

 fluid is present. In addition to these characteristic signs, the car- 

 buncles and swellings under the skin, already described, will aid in 

 determining the true nature of the disease. The most reliable method 

 of diagnosis is the examination of the blood and tissues for anthrax 

 bacilli. This requires a trained bacteriologist. The fatal cases of 

 anthrax number from 70 to 90 per cent, and are usually more numer- 

 ous at the first outbreak of the disease. 



Differential diagnosis. — The diagnosis from blackleg may be made 

 by noting the subcutaneous swellings which appear upon the patient. 

 Those of blackleg are found to crackle under pressure with the finger, 

 owing to the presence of gas within the tissues, while the tumors of 

 anthrax, being due to the presence of serum, are entirely free from 

 this quality and have a somewhat doughy consistence. The tumors 

 of blackleg usually locate on the shoulder or thigh and are not found 

 so frequently about the neck and side of the body as are the swellings 

 of anthrax. The blood of animals dead of blackleg is normal, and 

 the spleen does not appear swollen or darkened, as in animals affected 

 with anthrax. ' The chief differences between anthrax and Texas fever 

 are that the course of the former is more acute and the blood of the 

 animal is dark and of a tar-like consistence, while in the case of Texas 

 fever it will be found thinner than normal. The presence of Texas 

 fever ticks on the cattle would also lead one to suspect Texas fever i« 

 regions where cattle are not immune from this disease. 



