CHANGES DURING PREGNANCY 551 



abnormalities have also been observed in normal persons (Ehrstrom *) 

 it cannot _be considered as being peculiar to pregnancy. In 

 Hoffstrom's case 2 there was an increased phosphorus retention, which 

 was associated with a diminished excretion of phosphates in the urine 

 and resembled in that respect the progressive nitrogen retention. 

 But the nitrogen was retained somewhat more actively than the 

 phosphorus, so that there was no strict parallelism. Altogether 

 56 gm. of phosphorus were retained during pregnancy, of which 

 18 gm. were fixed by the foatus, so that the maternal organism 

 showed a net gain of 38 gm. Similar results have been obtained by 

 Bar 3 and by Landsberg. 4 



(e.) Sulphur. Hoffstrom's observations are, as he himself states, 

 not conclusive, because the analyses for the sulphur intake were 

 vitiated by an error. His analyses of the excreted sulphur show a 

 progressive diminution of the total sulphur which is due entirely to 

 a diminution of the so-called " oxidised sulphur," the sulphur excreted 

 in the various kinds of sulphates. The so-called " neutral sulphur," 

 which is derived mainly from cystin and from the taurin of the bile, 

 showed actually an increase. The relative proportion of neutral 

 sulphur to oxidised sulphur, which is supposed to be about 1 : 5 in a 

 normal person, was in Hoffstrom's cases completely changed and was 

 1 : 2. Bar found a much higher excretion of total sulphur with 

 a relation of neutral sulphur to oxidised sulphur of 1 : 9. Landsl>erg 

 has been able to demonstrate a sulphur retention during the end of 

 pregnancy which was proportionate to the nitrogen retention. 

 Hoffstrom interprets the diminution of the oxidised sulphur in his 

 case as indicating a diminished store of bases in the body, while the 

 increase in the neutral, i.e. unoxidised sulphur, he interprets as being 

 due to a diminished power of oxidation on the part of the pregnant 

 organism. Murlin, however, has pointed out that this change in the 

 sulphur excretion can be explained as being the result of the progressive 

 sulphur retention, just as in the case of nitrogen. 



(/.) Chlorides. The first estimations of the chlorides of the urine 

 in pregnancy indicated no variation from the non-pregnant level 

 (Winckel 5 ). Repeated investigations have been carried out since 

 the discovery that a retention of chlorides may occur in nephritis 

 and lead to oadema ( Widal 6 ). 



1 Ehrstrom, "Zur Kenntniss des Phosphorumaatzes bei deni erwachsenen 

 Menschen," Skandin. Arch. f. Physiol., vol. xiv., 1903. 



2 Hoffstrom, loc. cit. 



3 Bar, loc. cit. 



4 Landsberg, loc. cit. 



5 Winckel, Studien ilber Stoffwechtd etc., Rostock, 1865. 



6 Widal, " La cure de dechloru ration dans le mal de Bright," Arch. < 

 vol. cxciii., 1904. 



