934 Rachitis. 



As a further cause of lime deficiency in tlie organism an 

 improper cliemical composition of the food-stuffs may be men- 

 tioned even though the calcium content be normal. Above 

 all the relation between the amounts of lime salts and of phos- 

 phoric acid appears to be of importance (Klimmer & Schmidt, 

 Ingle). The intestinal contents being alkaline, it may perhaps 

 be supposed that in such a case a mutual precipitation of these 

 salts takes place in the intestinal canal, or that an excess of 

 free phosphoric acid is formed and, owing to this, a prolifera- 

 tion of the osteoid tissue (Piitz, M. B. Schmidt, Ingle). On 

 the other hand an abnormally high content of the food in 

 potassium salts is to be considered. The effect of food-stuffs 

 rich in potassium may be explained thus, that the chlorine of 

 the HCl of the stomach is bound by the potassium salts and 

 that therefore the formation of hydrochloric acid is reduced, 

 which would again lead to an insufficient solution and absorp- 

 tion of the lime salts that are present in the food principally 

 in insoluble form. According to H. Aron and Delcourt, how- 

 ever, the potassium salts tend to impede the deposit of lime 

 into the new-formed bony substance. In food-stuffs which con- 

 tain much sulphuric acid the lime salts help to form gypsum 

 which dissolves with difficulty, and they are therefore absorbed 

 less readily in the intestine. With this assumption, the observa- 

 tion of Haubner would agree, namely, that in the surroundings 

 of metal factories near Freiberg animals acquired rachitis and 

 osteomalacia, because the smoke contains arsenic, lead and 

 sulphurous acid. When the sulphurous acid was collected in 

 condensators both diseases ceased to occur. 



Digestive disturbances of whatever origin are also capable 

 of producing a deficiency of lime in the organism, either by in- 

 terfering with the formation of HCl in the stomach (Seemann, 

 Zander) or with the intestinal absorption ; Imt also, and possibly 

 very decidedly, by increasing the normal elimination of the 

 calcium compounds in the intestine, a possiliility that must be 

 considered especially in protracted intestinal catarrh. 



A second etiological factor of rickets is found in intoxica- 

 tion. Wegener (1872) who produced rachitis in animals by 

 long continued feeding of phosphoric acid, Avithdrawing the lime 

 at the same time, attributed to phosphoric acid an irritating 

 action upon the bone-forming tissues. A similar view was 

 expressed later by Piitz (1874). But Kassowitz (1878) showed 

 that the administration of slightly enlarged amounts of phos- 

 phorus suffices of itself to produce a disease similar to rachitis. 

 On the basis of his experiments Kassowitz assumed the action 

 of a substance circulating in the blood which is similar to phos- 

 phorus. Lehnerdt caused similar changes with strontium, but 

 lield them to be different from rachitis because, in contrast to 

 rachitis the new-formed tissue is capable of taking up lime 

 salts. The intoxication theory received further support in the 

 results of experiments undertaken by Ostertag and Zuntz (1907) 



