PRINCIPLES OF VETERINARY SURGERY 583 



OSSEOUS TISSUES : GENERAL AFFECTIONS. 



RACHITIS. 



Rachitis and Osteomalacia are general diseases of the os- 

 seous system due to disturbances of the nutritive function. 

 The two processes are very grave. They have often been 

 confounded, but are, however, clearly separate conditions. 

 Rachitis is a disease of the young, occurring during the pe- 

 riod of growth, while osteomalacia is an abnormality of the 

 adult. 



DEFINITION. — Rachitis is a disease of young animals, 

 characterized by aberrations of physiological ossification, 

 which produce transient or lasting deformities of the skel- 

 eton. It is constitutional dystrophia of the bones which 

 seemingly depends upon, in general, disturbances of nutri- 

 tion reflected over the entire anatomical apparatus. It is 

 observed in man and in most of the domestic animals. It 

 especially attacks pups and pigs, and is somewhat rare in 

 the colt, the calf and the lamb. It is also quite frequent 

 in poultry and in wild animals kept in captivity, — the lion 

 the tiger, the ape, etc. 



ETIOLOGY AND PATHOLOGY.— The causes of ra- 

 chitis have remained obscure, in spite of the numerous stud- 

 ies undertaken to determine them. Its study must, therefore, 

 revert to an investigation of the influence of age, species, 

 race, heredity, hygienic conditions and alimentation; an ex- 

 amination of the dififerent opinions advanced in its patho- 

 genesis, and the researches made with the view of reproduc- 

 ing it. 



The influence of age is certain. The young alone are 

 attacked. It sometimes begins in the intra-uterine life,- — 



congenital rachitis, — but more frequently after birth, — 



acquired rachitis, — during the first year, before the epiphy- 



