CHAPTER XXXIV. 



THE BACILLUS LACTIMORBI OF TREMBLES. 



Occurrence. The disease known as milk sickness, sick stomach, 

 swamp sickness, tires, trembles, slows, etc., is an affection of cattle, 

 and occasionally of sheep. It has been observed in the United States 

 for over one hundred years, and apparently has never been described 

 in any other part of the world. It was formerly more frequently 

 mentioned, and has evidently decreased considerably. An affected 

 animal is lifeless, tired out on the slightest exertion, and the muscular 

 weakness is manifested by trembling, which characteristic symptom 

 has led to the designation "trembles." In a more advanced stage 

 there is stiffness of the joints, great weakness and the animal is unable 

 to get up after it has once fallen to the ground. 



Pathologic Lesions. Jordan and Harris describe the pathologic 

 lesions of the disease in cattle as follows : There are no characteristic 

 external changes, but upon opening the body the smell of acetone 

 can often be detected. Occasionally a small quantity of clear yellow 

 fluid is present in the pleural cavity. The lungs are edematous. The 

 visceral layer of the pericardium, chiefly along the course of the cardiac 

 veins from base to apex, and around the roots of the large vessels, 

 shows ecchymotic spots, which are also occasionally seen in the 

 parietal layer of the peritoneum. The liver is much enlarged, of a 

 purple red color, and much congested; it appears mottled in con- 

 sequence of the presence of areas of fatty degeneration, of which it 

 shows marked evidences on section; the consistency of the organ is 

 much diminished. The spleen is not enlarged. The kidneys are 

 enlarged, congested, and sometimes show evidences of parenchymatous 

 degeneration. The mucosa of the small intestines is congested, and 

 shows ecchymotic spots, and the jejunum and the upper part of the 

 ileum are covered by a yellowish, very tenacious mucus. 



The disease appears to be usually contracted by grazing cattle or 

 sheep which have entered an infected territory. It may then be 

 communicated to man through raw milk or butter, or through raw 

 or insufficiently cooked meat; dogs and cats may also become infected. 

 The mortality in man is claimed to be high, but this is probably 

 incorrect, because, as a rule, severe cases only are recognized while the 

 milder cases have escaped notice. 



Morphology and Staining Properties. Jordan and Harris isolated 

 an aerobic organism which they called Bacillus lactimorbi from the 

 internal organs of cattle dead from trembles. They describe it as 

 follows: In cover-glass preparations made from the juice of the 



