536 THE PHYSIOLOGY OF REPRODUCTION 



the amount of acetone bodies present can be obtained in a few minutes 

 by the proper application of Eothera's test, and a test-tube is the 

 only apparatus required. 



Other aspects of the acid-base equilibrium during pregnancy will 

 be dealt with below in a separate section. 



The only feature of the urine of pregnancy which could not be 

 explained satisfactorily by Murlin was the presence of creatin. 

 Folin, as a result of his observations on the composition of the urine 

 of normal adult men, had stated that on a creatin-free diet creatin is 

 absent from normal urine. This statement was generally accepted, 

 and the excretion of creatin in the urine was therefore taken as a 

 sign of an abnormal metabolism, and far-reaching speculations were 

 based on it. These speculations were deprived of their basis, at least 

 so far as pregnancy is concerned, when it was found that normal 

 women frequently and children always excrete creatin, even when on 

 a creatin-free diet.^ ' 



Post-partum there is a rise in the excretion of total nitrogen 

 which is independent of the food. It occurs rather suddenly at about 

 the sixth or seventh day. There is also an increase in the excretion 

 of creatin. These changes are probably related, as Murlin suggests, 

 to the involution of the uterus. 



The albuminuria of pregnancy in the human female is not strictly 

 physiological. Regarding its frequency very varying figures have 

 been given, ranging from five per cent, to sixty per cent. It appears 

 in the second half of pregnancy, gradually increases up to the time of 

 birth, and quickly decreases in the puerperium. In fifty per cent, 

 of the eases it has already disappeared on the fourth day after labour. 

 The protein is of renal origin, and in a typical case amounts to O'Ol 

 to 0"05 per cent. That it is not due to mechanical pressure on the 

 renal vessels or ureter, or to increased intra-abdotaiinal pressure 

 seems certain. Nor has any definite proof been given of the influence 

 of a toxin arising in the foetus, and causing degeneration of the renal 

 epithelium. Veit ^ explains it by his hypothesis of the presence of 

 placental constituents in the maternal circulation. Metabolic 

 investigations in pregnancy complicated by albuminuria show nothing 

 characteristic (Magnus-Levy ^). 



A special constituent of the urine may be found during the 

 puerperium. Though called peptone (Fischel *), it really consists of 



' Krause and Cramer, "Sex and Metabolism," Proe. Phys. Soc, Jour, of 

 Physiol., vol. xlii., 19] 1. Krause, "On the Urine of Women under Normal 

 Conditions, etc.," Qiuir. Jour. Exp. Phys., vol. iv., 1911. Krause, "On Age 

 and Metabolism and on tbe Significance of the Excretion of Creatin," ibid., 

 vol. vii., 1913. 



^ Veit, "Ueber AJbuminurie in der Schwangerschaft," Berlinklin. Woch., 1920. 



^ Magnus-Levy, see v. Noorden, loc. cit. 



* Fischel, " Peptongehalt der Lochien," Arch. f. Gyniih., vols. xxiv. and xxvi. 



