602, PRINCIPLES OF VETERINARY SURGERY' 



many writers. Aside from these influences which depend 



upon the external environment, gestation and lactation 

 play an important predisposing role. They modify and de- 

 press the nutritive movements of the body, and from the 

 standpoint of osseous cachexia they play the part that trau- 

 matisms do in certain infections. During gestation the 

 female should supply the needs of the foetus, and convey to 

 it the salts required to construct the skeleton, and as 

 growth occurs, both before and after parturition, in spite of 

 the mother's deficiencies in this connection, the needs of the 

 skeleton are borrowed from all of the organs containing 

 them. The mother supplies the new-born an average of 

 6.64 grams of salts per day, which she draws not only from 

 her blood but also from any of the organs capable of fur- 

 nishing them, and even from the nervous system itself. If 

 these elements are not furnished in the food materials 

 transferred to the young, the mother's tissues are impov- 

 erished, resulting in an abnormal construction of all new 

 tissues formed in both the foetus and the mother. The ces- 

 sation of lactation is nearly always followed by a spontan- 

 eous amelioration; but the disease resumes its course at the 

 next period of gestation. All of these influences tend to 

 produce the same pathological results, — an incomplete nu- 

 trition of the skeleton, which is so vitiated as to destroy the 

 equilibrium between assimilation and disassimilation. 



The theory of acids and that of inflammation complete 

 the subject of its etiology. According to the first, lactic acid 

 by dissolving the salts, in excess, would cause osseous cach- 

 exia. This theory is supported by the experiments of 

 Heitzmann, and is defended by Bouchard (see rachitis). It 

 is very debatable, as the experiments and the resulting facts 

 in its favor are bj no means convincing. The latter theory 

 is that of inflammation, said to be caused by an irritant cir- 

 culating in the blood — phosphorus, or some infectious mat- 



