576 Veterinary Medicine. 



unfavorable to the idea of immunit}-, and rather favors that of 

 debihty or cachexia. 



Lesions. These are confined to the bones. Decalcification in 

 the Haversian canals and cancelli, reduces the bony tissue to a thin 

 soft plate. Yet the condition is not constant. Gravvitz found no 

 special dilatation of the canals or cancelli in colts. Nessler and 

 others found decrease of the lime salts, Bibra and Grouven de- 

 tected no marked change, and Hoffmann, and Begemann found 

 an actual excess of phosphates. Doubtless the specimens se- 

 lected and the stage of the disease, whether in active progress or 

 during convalescence, may somewhat explain discrepancies. The 

 fat cells increase in the cancelli, with more or less hyperaemia, 

 and even blood staining as the disease advances, the bone cells 

 become less branching, and there may be gelatinoid exudates. 

 The resistance of the bone is diminislied, it may be indented 

 with the finger, or .scraped off with the nail, or cut with a knife. It 

 breaks under a slight strain, and is easily crushed under the 

 weight of the animal so that fractures and distortions of all kinds 

 are met with. In breeding cows the earliest and most marked 

 lesions are in the pelvic bones, but fractures of the bones of the 

 limbs are common. 



Symptoms. Poor condition or even emaciation, with very vis- 

 ible projection of the bones is common. The coat is rough, the 

 skin tense, inelastic and hide bound, appetite variable, sometimes 

 impaired, and nearly always perverted so that the patient will 

 lick the manger continually or pick up and chew all .sorts of ob- 

 jects, bones, leather, articles of clotliing, pieces of wood or iron, 

 stones, etc. The amount of food consumed ma}', however, be up 

 to the normal. The most marked feature is the difficulty and 

 stiffness of locomotion. Tiie patient lies most of the time, rises 

 languidly and with difficulty and moves the limbs as if each were 

 a rigid post without joints. The hocks will knock together, and 

 the restricted movements of the joint are often attended by crack- 

 ing. Yet appetite, temperature and yield of milk may remain 

 normal. 



Later appetite and milk secretion fail, temperature rises a de- 

 gree or two, the animal refuses to rise, remaining down twelve 

 to twenty-four hours at a time, and rising first on the hind parts, 

 and remaining on the knees for a length of time, moaning and 



