DISEASES OF THE ORGANS OF LOCOMOTION. 



DISEASES OF THE BONES. 



Rachitis. 



(Rickets.) 



Etiology. — The different theories -which have been advanced con- 

 cerning the origin of rachitis do not seem to answer in all cases. These 

 theories are as follows; it is due to a deficiency of lime-salts as a conse- 

 quence of disturbances of digestion; to excessive formation of lactic acid, 

 in the blood and to salts of potassium in the milk or to a lack of hydro- 

 chloric acid in the gastric juice, 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 blood-vessels in the osteogenetic tissues, so that 

 the lime-salts continue to circulate in the blood instead of being deposited 

 in the bones. Xone of these theories stands the test of close observation, 

 we therefore do not know positively anything relating to the character 

 and origin of rachitis. It is, perhaps, better to admit that it is a specific 

 etiological change (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 especially bones, as it has 

 been demonstrated that animals with this disease if given these articles 

 of diet seem to improve immediately. Insufficient food to the bitch 

 during gestation, or trying to raise too large a litter, or early weaning, 

 improper food, keeping animals in cellars or in dark, damp places are all 

 factors that tend to cause rickets. A proper amount of exercise is 

 especially 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, as is frequently seen as a result of 

 very close breeding and also in breeds where color or conformation is the 

 chief object, such as bull terriers, collies, or great danes, and where a 

 breed is not old enough to be established, as Boston terriers. The 

 symptoms appear relatively in proportion to their growth. If the puppy 

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

 comes on gradually. 



Pathological Anatomy. — Rickets consists of a peculiar disturbance 



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