532 IOWA DEPARTMENT OF AGRICULTURE 



ordinary circumstances, the bacilli are likely to be present in the milk 

 withdrawn from any of the cows. It is possible that in every fatal case 

 of anthrax in a milch cow, the bacilli are present in the milk at the 

 time of death, but it is also probable that the milk invasion does not 

 occur until the bacilli have begun to multiply in the circulating blood, 

 and it is well known that that is an event which usually precedes death 

 only by an hour or two. While the period of invasion may vary, and 

 the time between the onset of the invasion and death may vary, no ani- 

 mal has a normal temperature after the germ begins to multiply in the 

 blood. "It therefore appears safe to conclude that there is no danger 

 from the milk of an infected cow prior to a distinct rise in temperature. 



The nature and extent of tissue changes depend upon the course 

 of the disease, and any, or all, clinical changes may be absent. An- 

 thrax carcasses soon loose their rigidity and become bloated. Often a 

 blood stained fluid flows from the natural passages. The spleen is 

 usually enlarged from three to five times, the pulp blackish and soft, 

 and occasionally disintegrated. The blcod is usually dark with a tarry 

 consistency and varnish lustre, showing little tendency to coagulate. 

 It does not assume its normal color when exposed to the air. Hemorr- 

 hages varying in amount from petechiae to extravasations, distended 

 capillaries and gelatinous effusions or a simple serous oedema may 

 occur. The lymphatic glands may be hemorrhagic, oedematous or both. 

 Oedema of the connective tissues of the neck is often very marked. In 

 the abdomen, the thoracic cavity and the perocardial sac more or less 

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

 carbuncles already described, often aid in determining the true nature 

 of the disease. While all the foregoing lesions may be absent in the 

 very acute cases, the specific organism is always present in the cadaver. 



Prognosis. In most herds the mortality is nearly 100 per cent, with 

 an average of 70 per cent, of all animals affected. 



DIFFERENTIAL DIAGNOSIS. 



The suddenness of attack and short duration of the disease may 

 confuse one in differentiating cases of poisoning, heat exhaustion, cereb- 

 ral appoplexy, death from lightning or pulmonary congestion. Little 

 room for doubt, however, can be left where proper bacteriological exami- 

 nations have been made. 



PROTECTIVE INOCULATION. 



Much has been written regarding the virtue of various vaccines. And 

 after all discussion has been gone over thoroughly, the fact remains that 

 vaccinated animals continue to die regardless of the method of inocula- 

 tion. In Germany and England, the stamping out system is considered 

 superior to vaccination. To this end, rigid laws have been enacted as 

 the only reliable means of suppressing the disease. 



