DISEASES OP THE BONES AND 

 ARTICULATIONS. 



Bhachitis. 

 [Rickets.) 



Etiology. The different theories which have been advanced 

 concerning the origin of rhachitis do not seem to answer in some 

 cases (a deficiency of lime-salts as a consequence of disturbances 

 of digestion ; excessive formation of carbonic or lactic acid, which 

 would dissolve the lime-salts; an alteration of the general nutritive 

 condition on account of abnormal influences in young animals; 

 inflammatory hypersemia and an increase in the number and size 

 of bloodvessels in the osteogenic tissues, so that the lime-salts con- 

 tinue to circulate in the blood instead of being deposited in the 

 bones). We therefore do not know positively anything relating 

 to the character and origin of rhachitis. It is, perhaps, better 

 to admit that it is a speciflc disorder (which has not as yet become 

 positively known). We know positively, however, that rickets 

 can be developed in the dog by deficient, improper food, by want 

 of meat, and iespecially bones, as it has been demonstrated that 

 animals with th s disease if given these articles of diet seem to 

 improve immediately. A proper amount of exercise is specially 

 important for puppies kept in a small place. 



Rickets generally appears in young animals in the first few 

 months of their life. It is often hereditary. The symptoms 

 appear relatively in proportion to their growth. If the animal 

 grows quickly, rickets appears quickly; if it grows slowly, the 

 disease comes on gradually. 



Pathological Anatomy. Rickets consists of a peculiar dis- 

 turbance of the bones of the whole system. It seems to be due to 

 a deficiency of lime-salts in the bones, making them soft and flex- 

 ible. At the same time the nutritive process in the perios- 

 teum seems to be changed. The bones are light and soft enough 

 to cut with a knife, and the epiphyses of the long bones are very 

 much thickened ; the marrow and periosteum are reddened. When 

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