RICKETS 313 



factors in discussing the etiology of this disease. The missing sub- 

 stance is found in good breast-milk and in cod liver oil, but not in 

 certain milk preparations and flours. It has nothing to do with a 

 lack of fat, protein or calcium, per se, as has been often stated, but 

 with a vitamine which we call "antirachitic vitamine," either 

 belonging to or identical with the type of A-vitamine. In what 

 way the lack of vitamine A brings on all of the known symptoms of 

 rickets, is at present unknown, and we find ourselves upon the same 

 uncertain foundation characteristic of the explanation of all other 

 avitaminoses. 



OCCURRENCES 



According to the newly found facts, it is unlikely that the diseas3 

 is associated with any definite age, although it seems certain that it 

 is manifested mostly during the period of active bone growth. 

 Rickets occurs very frequently and we need mention only two investi- 

 tigations to illustrate this. Schmorl (1031) stated that on post- 

 mortem of the cadavers of children under 4 years old, 90 per cent 

 showed signs of rickets. Schwartz (1032) observed among 4944 

 cases, 15 per cent craniotabes in the first year; 35 per cent showed 

 rosary (of which 13 per cent were in the first month). Congenital 

 rickets too was observed with certainty (Kassowitz, 1032a) . Mery 

 and Parturier (1033) saw a case in a 6-weeks old child. Wieland 

 (1034) reported on this too, but he (1035) did not believe in the exis- 

 tence of congenital rickets. Sinclair (1036) and Carr (1036a), held 

 that premature children contract rickets very easily, since the neces- 

 sary reserve material has not yet been prepared. Hamilton (1037) 

 has described craniotabes in the second month among premature 

 babies. Retterer and Fisch (1038) describe a case of congenital mi- 

 cromelia which they regarded as rickets. Since rickets may occur at 

 any age, the cases of hereditary rickets are not puzzling; the mother 

 may be suffering from a lack of vitamine A during pregnancy, when 

 the requirements are even greater than normally. Among the cases 

 of "osteogenesis imperfecta," there are, to all appearances, those that 

 may be classified as congenital rickets. On the other hand, some 

 of them must be regarded as hereditary osteoporosis, with a poor cal- 

 cium assimilation. Ostheimer (1039) described a condition in chil- 

 dren, called "fragilitas ossium," resembling osteoporosis (lack of cal- 

 cium), which in this case could be improved not by a calcium or cod 



