RACHITIS. 



articulations. The latter are deformed, and on palpation are found to 

 be surrounded by uneven and irregular growths. 



The front limbs are distorted. In young pigs, lambs, and less 

 frequently in foals, calves and dogs, the jaws become deformed, and 

 mastication is rendered difficult. 



The vertebral column may also l)e affected, and lordosis (bending 

 downwards of the l)ack) or skoliosis (lateral bending of the back) is some- 

 what frequent. 



Cyphosis, or ui)ward l)ending of the back, seldom occurs, and when 

 seen, sometimes results from disease other than rachitis. 



General development is always in- 

 terfered with and the young creatures 

 are generally' dwarfed. 



The digestive apparatus is dis- 

 ordered, the appetite is irregular and 

 sometimes depraved, w^hile indiges- 

 tion, gastritis, and enteritis are not 

 exceptional. Physiological and patho- 

 logical research has shown that the 

 quantity of phosphoric acid elimi- 

 nated in twenty- four hours in a 

 rachitic child is double the quan- 

 tity passed b}^ a healthy infant. 

 The amount of urea in the urine 

 (whicli is a criterion of nutrition, and 

 usually varies in proportion to the 

 amount of food ingested) is, on 

 the contrary, diminished even when 

 highly nitrogenous food is given, 

 thus suggesting diminution in nu- 

 trition. 

 Lesions. The lesions are represented by abnormal and irregular 

 tliickening around the inter-articular cartilages. The cartilage is 

 thickened, compressible, very spongy and without regular ossification. 

 Diffused periostitis exists principally towards the extremities of the bone. 

 Beneath the periosteum the surface of the bone appears rough and 

 softened. On section the medullary canals are seen to be enlarged and 

 filled with marrow of a gelatinous character. The Haversian canals are 

 dilated, and the entire tissue appears very vascular. Chemical analysis 

 proves that the mineral constituents of the bone, particularly the phos- 

 phates, have diminished by one-half ; the organic constituents on the 

 other hand are increased in a similar ratio, but the ossein is abnormal. 

 Ossification has, in a word, been incomplete. 



Fig. 1.— liachitis ui a voiui" ''oat. 



