CHAPTER II. 



DISEASES OF METABOLISM AFFECTING 

 PRIMARILY THE BONES. 



RACHITIS. RICKETS. 



Definition.— A disease of young animals, characterized by 

 impaired nutrition of the entire body and disturbances and 

 changes in the growth of the bones leading to marked 

 deformity. 



Occurrence.— The disease is rather widespread, appearing 

 in nearly all countries. Animals in some countries are very 

 commonly affected, while in others the disease is not so 

 prevalent. Young animals, as a rule, become affected during 

 the first few weeks of life, or at about weaning time. The 

 condition is observed more commonly in dogs than in any 

 of the other small animals. Cats and rabbits are not very 

 often affected. Fowls occasionally suffer from the disease, 

 especially chickens and pigeons. It is commoner in the 

 larger breeds of dogs and fowls, perhaps due to their more 

 rapid growth during early life. 



Etiology.— Various factors have been given as the cause of 

 rachitis : (a) Due to a deficiency of lime salts in the organism. 

 This is no doubt one of the most important causes of the 

 condition, as it develops most frequently in the breeds that 

 grow rapidly, and at a time in the animal's life when there is 

 apt to be a deficiency in the amount of lime salts ingested. 

 Clinical and experimental evidence tend to prove the accuracy 

 of this statement, (b) Improper assimilation of lime salts 

 due to a lack in the acid content of the gastric juice preventing 

 the lime salts from being dissolved and consequently not 

 absorbed. Foods rich in potassium salts reduce the hydro- 

 chloric acid content in the stomach leading to an insufficient 



