A practical course of chemical physiology / by D. Noël Paton and Edward P. Cathcart.
- Diarmid Noel Paton
- Date:
- 1910
Licence: In copyright
Credit: A practical course of chemical physiology / by D. Noël Paton and Edward P. Cathcart. Source: Wellcome Collection.
Provider: This material has been provided by The University of Glasgow Library. The original may be consulted at The University of Glasgow Library.
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![N between the amount of - alkali in c.c. required to completely N neutralise the — H2S04 and the amount of N Ho SO 2UU1 10 ‘ * 10 originally taken gives the amount of NH3 = 1ST distilled over. 1ST Ex. If 60 c.c. — HoS04 be taken in the first place, and 10 N during the titration 25 c.c. — NaOH are required, then N 60 c.c. — 25 c.c. = 35 c.c. — HoSCh neutralised by NH„ evolved 10 17 3 N N N 35 c.c. — H9S04 = 35 c.c. — NH„ = 35 c.c. — N; 10 2 4 10 3 10 ’ isl- and as 1 c.c. — N = ‘0014 grins. N, 10 6 then in 5 c.c. urine there is 35 x ’0014 = ‘049 grms. 1ST. II. Estimation of Urea. 1. By Bolin’s Method. Weigh 20 grms. crystallised magnesium chloride into an Erlenmeyer flask (250-300 c.c. capacity), then add with a pipette 5 c.c. of urine, 6 c.c. concentrated HC1, a piece of hard paraffin about the size of a hazel nut, and finally a drop or two of an aqueous solution (1 per cent.) of alizarin red. A special safety tube is then inserted, and the mixture boiled until distinct “ bumping ” commences. When this appears the heat is lowered so that bumping still goes on, but not quite so energetically. Heating is continued for at least two hours. The contents of the flask must never become alkaline. If the indicator shows any appearance of red a few drops of the acid distillate which collects in the safety tube must be added by tilting the tube forward. [When the safety tube is running properly there ought to be a slow but steady return constantly going on.] At the end of the necessary period the contents of the Erlenmeyer flask are transferred to a distilling flask, as in the Kjeldahl method, and the same](https://iiif.wellcomecollection.org/image/b24932656_0077.jp2/full/800%2C/0/default.jpg)
