90 



Mr. E. Mellanby. 



[Oct. 3, 



The red colour, which may be developed by mixing extracts of uterine 

 muscle with alkaline picric acid, disappears rapidly on dilution, and cannot, 

 therefore, be due to creatinin. Consequently, Shaffer's explanation, as it 

 stands, does not adequately explain the puerperal excretion of creatin. 

 However, it is possible that, although uterine muscle contains no creatin, 

 yet some substance is present in the muscle which is converted into 

 creatin when that tissue involutes, and appears ultimately in the urine. In 

 order to test this point, the following observations were made. 



In a lying-in ward two women were delivered of children by Caesarian 

 section, the one case (A) because of a contracted pelvis, the second case (B) 

 because of a ruptured uterus. At the time of operation the uterus in 

 Case A was stitched up and retained, while in Case B, with the ruptured 

 uterus, it was completely removed. If the involution of the uterus is 

 accountable for the postpartum excretion of creatin, then it is clear that 

 Case A would excrete much more creatiu than Case B, where there was no , 

 uterus to involute. 



A. Caesarian Section. Uterus 

 stitched up and retained. 

 Operation January 13, 1910. 



B. Caesarian Section. Uterus 

 removed. 

 Operation January 16, 1910. 







Total 



Total 



Creatin 





Vol. 



creatin. 



creatinin. 



Creatinin 





c.c. 



grm. 



grm. 



0-96 



Jan. 14 



815 



0-987 



1 -03 



„ 15 



650 



0-87 



0-91 



0-95 



„ 16 



450 



0-58 



0-54 



1-08 



„ 17 



650 



0-72 



0-7 



1 -03 



„ 18 



1200 



0-7 



0-97 



0-72 



„ 19 



1650 



0-7 



0-86 



0-89 



Vol. 



Total 

 creatin. 



Total 

 creatinin. 



Creatin 

 Creatinin 



c.c. 

 Spec. 



mgrm. in 

 10 c.c. 

 9-7 



mgrm. in 

 10 c.c. 

 10 



0-97 



• 2500 



grm. 

 3-8 



grm. 

 1-75 



2-13 



1270 



1-76 



1 -27 



1 -38 



Jan. 17 

 „ 18 

 „ 19 

 „ 20 

 „ 21 



These figures show that the removal of the uterus did not prevent the 

 excretion of creatin, and in fact, Case B, where there was no uterus to 



Fortunately, creatinin has a much more potent action than other physiological reducing 

 agents and carries on the reaction very quickly with the formation of di-amino- 

 mononitrophenol — a red substance which retains its intensity on strong dilution. The 

 end product of sucli reducing agents as dextrose, levulose, maltose, aldehyde, is generally 

 mono-aminodinitrophenol, which is also a red substance, but loses all colour intensity on 

 dilution [Chapman (15)]. 



This explains why the full dilution of Folin's method of estimating creatinin is 

 absolutely essential ; for it is clear that on small dilution the colour of the mono-amino- 

 dinitrophenol will interfere with that of diaminomononitrophenol. This point concerning 

 dilution is a common source of error in recent research on creatinin. 



