Licence: Public Domain Mark
Credit: The diseases of the stomach / by Dr. C.A. Ewald. Source: Wellcome Collection.
Provider: This material has been provided by the Augustus C. Long Health Sciences Library at Columbia University and Columbia University Libraries/Information Services, through the Medical Heritage Library. The original may be consulted at the the Augustus C. Long Health Sciences Library at Columbia University and Columbia University.
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![10 c. c. of stomach contents obtained one honr after the test break- fast ranges between 4 to 5 or 5 to 6 c. c.; results above or below these limits are pathological. It is a matter of convenience to ex- press the acidity in percentage according to the amount of the deci- normal soda solution used; thus, for example, 61 per cent acidity would mean that 100 c. c. of filtered stomach contents were neu- tralized by 61 c. c. of a deci-normal soda solution. This prevents any misconception that the acidity depends on free hydrochloric acid. If we are sure that the acidity depends on the latter, and not on salts or any other acids, we may express the value as HCl. Let us take an example: 61 c. c. of deci-normal soda solution had to be added to 10 c. c. of stomach contents until the end reaction ap- peared. One cubic centimetre deci-nqjrmal soda solution being equivalent to 0*00364:6 HCl, when 10 c. c. of stomach contents are used, multiply 0-03646 by the number of cubic centimetres added from the burette till the contents of the beaker are neutralized; this will give the percentage of HCl in the stomach contents under examination. Thus in the example the actual percentage of HCl is 0-22 per cent; this result is within the normal limits (0'14 to 0*24 per cent). To determine whether the acidity depends on free acids or acid salts, the aniline dyes will be found the most useful; of these the best is TropcBolin 00—Vorange Poirier of the French. This powder, when dry, has a beautiful orange color; in saturated watery or alcoholic solutions it is a dark yellowish red ; in the presence of traces of free acid—even as little as about 0-25 per thousand [1 in 4,000]—it changes to dark brown, but acid salts make it straw yel- low. Take a small quantity of the reagent and add a few drops of dilute HCl (containing about O'OS per cent pure HCl); the solution at once assumes a deep dark-brown color. If some acid sodium wendung verschiedener Indicatoren. Inaug. Dissert. Neuwied, 1891) has again directed attention, tliat the various indicators, rosolic acid, cochineal, fluorescin, litmus, curcuma, etc., give very different values for the so-called point of neu- tralization. Thus the acidity of a specimen of stomach contents was 65-8 with phenol-phthalein, 54-6 with rosolic acid, and 51-8 with litmus. An interesting dis- cussion of this subject has been published by Spitzer (Ueber die Benutzung gewisser FarbstofEe zur Bestimmung von AfRnitaten. Pfliiger's Archiv, Bd. iv, p. 551). Hence it is necessary to always employ the same indicator.](https://iiif.wellcomecollection.org/image/b21223026_0048.jp2/full/800%2C/0/default.jpg)
