586 PRINCIPLES OF VETERINARY SURGERY 



the disease, and that the augmented elimination of calca- 

 reous salts is a symptom and not a cause. 



He proves that lactic acid, while increasing the elimina- 

 tion of alkaline salts, does not produce rickets; that the 

 lactic ferment, while making the calcareous salts of the food 

 hard to absorb, does not cause rickets ; and, finally that the 

 potassium salts have a marked action on the cartilages in the 

 stage of growth, and that they produce lesions character- 

 istic of rickets, probably by removing salts of sodium from 

 the organism that are necessary for the ossification of the 

 primitive cartilages. These etiological factors may be 

 summed up as an insufficiency of phosphates, which may be 

 due to a diminution of the acidity in the intestinal secre- 

 tions. Bouchard states that phosphates are not absorbed, 

 but that phosphoric acid is assimilated as an alkaline phos- 

 phate, especially of phospho-glyceric acid, and calcium in 

 the form of an alkaline or organic salt. Phospho-glyceric 

 acid is produced in the duodenum. Phosphoric acid is gener- 

 ated by the action of the hydrochloric of the gastric juice, and 

 is combined with the nascent glycerin resulting from the 

 breaking up of the fats by the pancreatic juice. This phos- 

 pho-glyceric acid is afterwards combined with the calcium 

 in the tissues on the way to ossification. These successive 

 reactions could not take place in every instance of altera- 

 tions in the gastro-intestinal apparatus. That is to say, 

 that the principal cause of rachitis would depend on a vic- 

 ious or defective operation of the functions of the stomach 

 and pancreas. Kassowitz regards this affection as the re- 

 sult of an inflammation of the osseous tissue, — an osteitis. 

 He claims that the exaggerated vascularization of the per- 

 iosteum prevents the deposition of calcium carbonate, but 

 these lesions are found in normal bones. Ossification in 

 young animals is accompanied by intense vascularization. 

 Rachitis has also been looked upon as an infectious dis- 



