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contents of mice inoculated with alveolar carcinoma (Jensen), and had 
found that there was, apparently, no decrease in this acidity as compared 
Hydrochloric Acid in the Gastric Contents in Cancer. 445 
with normal mice. 
We commenced our experiments in December, 1905, and have continued 
them with comparatively little interruption up to the present time. At the 
beginning of this year (1908) we were fortunate in obtaining a grant from 
the Imperial Cancer Research Fund, which, by enabling us to retain the 
services of a skilled assistant, rendered possible the completion of our work, 
in the course of which, during the last two and a-half years, we have had the 
opportunity of examining over 1000 stomachs of normal and of “ cancer” mice. 
Our primary object was to ascertain whether the suggested absence or 
marked diminution of free hydrochloric acid in the stomachs of human 
beings suffering from cancer occurred also in mice suffering from the same 
disease, whether spontaneously arising or the result of experimental trans- 
plantation. Obviously the method to be adopted for the determination of 
the hydrochloric acid was an important consideration, and after careful 
study of the various processes used by other investigators in similar work, we 
finally determined to employ Volhard’s method for the volumetric estimation 
of chlorides, the principle of which is based on the precipitation of the 
chloride by an excess of standard silver nitrate in the presence of free 
nitric acid and the subsequent determination of the excess of silver nitrate by 
means of ammonium thiocyanate, using iron alum as an indicator. | 
This method was ingeniously adapted by Litittke,* and further simplified 
by Willcox, for the purpose of estimating hydrochloric acid in gastric contents, 
and we have followed these adaptations with such further modifications as 
seemed to us necessary for our particular purposes. 
The special advantage of Volhard’s process, apart from its accuracy, is that 
the hydrochloric acid, free or combined, is precipitated as chloride of silver 
in presence of free nitric acid. There can therefore be no question as to the 
particular acid estimated, a point which has been raised, although in our 
opinion needlessly, in connection with the Morner Sjoqvist method of 
estimating free and combined hydrochloric acid (see later). 
Briefly, the modus operandi of the method as employed by us has been as 
follows :—The stomachs are counted, weighed, crushed, and macerated in 
water for about 12 hours, and the mixture made up to a known volume and 
filtered. The examination of the filtrate is then carried out in the following 
manner :—- 
(a) The total chlorides (free, inorganically and organically combined hydro- 
chloric acid) are estimated by Volhard’s method in an aliquot part. 
* ‘Deutsch. Med. Woch.,’ 1891, p. 1325. 
VOL. LXXX.—B. 
Na) 
A, 
