INFECTIOUS DISEASES OF CATTLE. 479 



ground completely exhausted. Breathing becomes fast and painful, 

 with frequent spasmodic jerks. 



The pulse is quick and weak and the temperature is 106° to 107° F. 

 An edematous, doughy, and painful swelling appears at the point of 

 infection. This tumefaction spreads more and more and will crackle 

 on pressure. In case of an open wound a fetid liquid and frothy 

 discharge is observed. The center of the swelling may appear soft 

 and jellylike, while the margin is tense, hot, and painful. The symp- 

 toms increase rapidly, resulting in coma and death. 



Lesions . — After death the fat and subcutaneous tissues surrounding 

 the infected area are infiltrated with a yellow gelatinous material con- 

 taining an orange- colored foam, due to the presence of gas bubbles. 



The muscles at this point are friable, spong>', and of a uniform 

 brownish tint, disassociated by gas and with a blood-tinged exudate. 

 This gangrenous tissue, when present before death, can be removed 

 without pain to the animal. The intestines are generally normal, but 

 they, together with the peritoneum, may be inflamed, and the lungs 

 are usually the seat of an edema. The spleen, liver, and kidneys re- 

 tain their normal appearance, in marked contrast with anthrax. 



Differentiul diagnosis. — Unlike blackleg this disease never appears 

 as an epizootic but in isolated cases. It may also be differentiated 

 from the former by the history of a recent parturition or surgical 

 operation, by the presence of an ext-enial injury at the site of the 

 swelling accompanied by a fetid liquid discharge, and the gangi-enous 

 appearance of the tumefaction. Man is susceptible to malignant 

 edema, but not to blackleg. Malignant edema may also be easily dif- 

 ferentiated from anthrax in that the blood and spleen are normal in 

 appearance, while in the latter disease the blood is dark and of a 

 tarlike consistency and the spleen appears swollen, injected, and 

 softened. The local tumor in malignant edema contains gas bubbles, 

 while in anthrax swellings these are absent. Inoculation experiments 

 of guinea pigs, rabbits, and chickens will also disclose the differences 

 among the above three diseases, since all of these species are killed 

 by the germ of malignant edema, only the first two species by the 

 anthrax bacillus, while the guinea pigs alone will succumb to the 

 blackleg infection. 



Treatment. — Treatment is chiefly surgical and consists in laying 

 the infected areas wide open by free incision, followed by a liberal 

 application of a 30 per cent solution of hydrogen dioxid and subse- 

 quently a 5 per cent solution of carbolic acid. Usually the disease 

 when observed has advanced to such an extent that medicinal inter- 

 ference is without avail. Preventive treatment is by far the most 

 desirable, and consists, essentially, in a thorough disinfection of all 

 accidental and surgical wounds, the cleansing of the skin, and the 

 exclusion of soil, filth, and bacteria during surgical operations of any 



