EFFECT OX VARIOUS PHYSIOLOGIC PROCESSES 659 



species of animals studied, a decrease in the bone ash content occurs in 

 rickets, and a marked disturbance in ossification can be observed. An en- 

 largement of the growing epiphyseal cartilage takes place in all tubular 

 bones, which can readily be demonstrated by x-ray examination. The 

 deranged bone formation has been found to result from a reduction of a 

 Ca X P product in the blood, due to a decrease in the utilization of calcium 

 and of phosphate. This may be caused by a number of different factors. 



(2) The Absorption of Calcium and PhospJbate 



It is logical that an investigation of the pathology of rickets should start 

 with a study of what changes, if any, take placei n the composition of bones. 

 Thus, Korenchevsky^ cited IVIarchand,-^^ and others-'*^ •2'''' as having demon- 

 strated that rachitic bones were richer in water and poorer in calcium than 

 were normal bones; the main mineral constituents of the latter were known 

 to be calcium and phosphorus. The condition of rickets was therefore 

 ascribed to some abnormality in calcium and phosphorus metabolism which 

 resulted in the production of bones deficient in these elements. The bone 

 composition in osteomalacia was sho\\'n to be identical with that in rickets, 

 as reported by Frey,-^^ Weber, ^^^ and Huppert.^^o Weber ^^^ found a large 

 proportion of lactic acid in the bone substance and a reduced amount of 

 calcium. These findings led to studies of mineral metabolism, particularly 

 that of calcium, in relation to the composition of bones. Classical reports 

 of the early period include that of Chossat^^^ in 1842, and later those of 

 Edwards,252 Weiske,^^^ and Voit.-^^ 



a. Balance Experiments on Calcium and Phosphate Metabolism in 

 Rachitic Infants without and with Vitamin D. Evidence has been accumu- 

 lated which indicates that an increased loss of calcium and phosphate in the 



2^* R. F. Marchand, /. prakt. Chem., 27, 83-97 (1942); also cited by V. Korenchevsky, 

 Med. Research Council (London), Spec. Kept. Ser., No. 71 (1922). 



^^^ E. Bibra, Chemische V ntersuchungen iiber die Knochen und Zdhne des Menschen und 

 der Wirhelthiere, niit Rucksichtigung auf ihre physiologischen und pathologischen Verhdlt- 

 nisse, Schweinfurt, 1844; cited bv R. Xicolaj'sen and N. Eeg-Larsen, Vitamins and Hor- 

 mones, 11, 29-60(1953), p. 30. 



*^' A. Friedleben, Physikallsche und chemische Constitution wach^ender und rachitischer 

 Knochen, Wien, 1860; cited by R. Nicolavsen and N. Eeg-Larsen, Vitamins and Hor- 

 mones, 11, 29-60 (1953), p. 30. 



2« H. Frey, Zentr. med. Wissensch., 1, 28-29 (1863). 



"9 O. Weber, Virchow's Arch, pathol. Anat. u. Physiol, 38, 1-15 (1867). 



250 H. Huppert, Zentr. 7ned. Wissensch., 5, 458 (1867). 



251 IM. Chossat, Compt. rend., 14, 451-456 (1842). 



252 M. A. M. Edwards, Compt. rend., 52, 1327-1329 (1861). 

 2" H. Weiske, Z. Biol. 7, 179-184, 333-337 (1871). 



25^ F. Voit, Z. Biol, 29, 325-397 (1892). 



