756 FRANCIS H. McCRUDDEN 



tration. Truzzi reported ninety-seven cases of osteomalacia treated 

 by castration. Seventeen per cent of the patients were not cured. 

 These results have not been selected to show that castration is not always 

 followed by cure, but include most of the results reported in the literature. 

 Most of these patients were not cured by castration, and most of those 

 called cured were not followed for any length of time. The longer such 

 patients have been followed, as in the cases of Fehling and McCrudden, 

 the smaller the proportion of cures. A case, reported by Hofmeier, 

 illustrates this point very well. In 1891 he reported a case of non- 

 puerperal osteomalacia cured (followed only for three months) by cas- 

 tration. No further report of the case appeared in the literature, but 

 many years later I became acquainted with Professor Hofmeier, who 

 told me that the patient soon relapsed. 



The evidence, then, is strongly against the hypothesis that osteo- 

 malacia is a disease of the ovaries. The supposed beneficial effect of 

 castration on puerperal osteomalacia is easily explained. It is usual 

 for osteomalacia to improve after the end of pregnancy and lactation, and 

 only relapse again during a subsequent pregnancy. If there is no sub- 

 sequent pregnancy, there is no relapse. 



Need of Calcium as a Cause of Puerperal Osteomalacia. If we bear 

 in mind the facts already pointed out regarding the active nature of bone 

 metabolism, we see one direction in which to look for the cause of osteo- 

 malacia. When the necessity of any food material is increased without 

 a corresponding increase in the supply, or when the supply is decreased, 

 as in starvation, the stores of that substance in the body are mobilized. 

 We are familiar with this process in the case of glycpgen and fat me- 

 tabolism; and evidence that the same thing occurs in the case of the 

 mineral constituents of the bones has been pointed out in the section on 

 normal metabolism. The periods of life during which the need for 

 calcium is greatest are (a) during pregnancy and lactation, when there 

 is a flux of calcium to the growing fetus and to the milk; and (b) dur- 

 ing the period of bone calcification in young children. And it is pre- 

 cisely at those periods (the exceptions will be taken up later) that rickets 

 and osteomalacia occur. 



The following calculation indicates what a large amount of calcium 

 must come from the skeleton of the mother during the later stages of 

 gestation. According to analyses made by Michel, on the average, 

 a seven months human embryo weighs 1024 grams and contains 0.8 per 

 cent (8.2 grams) CaQ; a full term fetus weighs 3335 grams and contains 

 1.4 per cent (46.Y grams) CaO. This indicates a gain of 38.5 grams in 

 sixty days or 0.64 gram a day, which is more than twice the average 

 daily retention of calcium (Hoffstrb'm). The figures are only rough ap- 

 proximations, but they indicate that considerable quantities of calcium 

 must be transferred from the bones of the mother to the growing embryo. 



