306 W. I. Card and I. N. Marks 



The food intake of the patient over this period was small 

 and at times negUgible. The magnesium content of the food 

 taken has been calculated from food tables and amounts to 

 105 m-equiv. She had no drugs containing magnesium and 

 no toothpaste was used. Of the intravenous fluids given 

 none appeared to contain magnesium. The makers (Bengers) 

 kindly sent us an analysis of the casein hydrolysate (Casydrol) 

 given which contained only negligible amounts of magnesium. 

 The only magnesium given intravenously was that given in 

 whole blood. The total negative balance over this period 

 therefore amounted to some 346 m-equiv. 



The weight of the patient at the beginning of the period was 

 34 kg. and, if we assume that the body at this stage contained 

 7 per cent fat, the total magnesium content of the body 

 according to the data of Widdowson, McCance and Spray 

 (1951) was 14-2 g. or 1,180 m-equiv. The patient therefore 

 over this period lost something like 25-30 per cent of her total 

 body magnesium. This calculation makes the assumption 

 that she was normal at the onset, but it is quite possible that 

 she was already depleted since she had had an ileostomy for a 

 month with an episode of intestinal obstruction needing 

 suction and fluid replacement. 



The balance studies which followed the institution of 

 therapy are shown in Fig. 2. The magnesium content of a 

 sample of the fistulous fluid and of the urine was estimated 

 daily and the output of magnesium calculated as described. 

 The serum magnesium was estimated every few days. 



The results show that with the therapy, the patient passed 

 into positive balance over this period and that in all she 

 retained some 279 m-equiv. of magnesium before the observa- 

 tions were discontinued. The results are in general accord 

 with the previous conclusions. 



The serum magnesium showed a low figure at the time 

 of symptoms and rose with therapy but the estimations 

 are perhaps chiefly of value in emphasizing how little use 

 can be made of them as an index of magnesium deficit in 

 the body. 



