Abstract
Ten dogs were fed a normal diet (125 gm. meat, 100 gm. cracker meal, 30 gm. bone ash, 15 gm. lard, 300 cc. water); 3 dogs were fed a diet comparatively high in carbohydrate (25 gm. meat, 150 gm. cracker meal, 30 gm. bone ash, 30 gm. lard, 350 cc. water); 2 dogs were fed a high protein diet (300 gm. meat); and 2 a diet high in fat (50 gm. meat, 50 gm. cracker meal, 30 gm. bone ash, 180 gm. lard).
Fifteen dogs were fed a diet which has been shown by Mellanby 3 to produce rickets in young dogs (175 cc. milk, 200 gm. white bread, 2 gm. NaCl). Of these, 4 were also fed 10 cc. of cod-liver oil daily; and 5 were irradiated with ultra-violet light for periods ranging from 40 min. to 3 exposures of 45 min. each on consecutive days. Four to six hours after the last feeding the dogs were killed by intravenous injection of amytal, and the alimentary canal removed. The contents of the stomach, duodenum, 2 ft. sections of the intestine, the caecum, and the colon were obtained and the pH determined.
112 determinations (15 dogs) were made both electrometrically and colorimetrically. In the other determinations the colorimetric method was used. Comparison of the two methods justifies reliance on comparative results as obtained colorimetrically. The average error of the colorimetric method, as compared with the electrometric, was 0.2 of a pH unit; the maximum difference was 0.39, and the minimum 0.1; in every case the error was minus.
The average acidities, in terms of pH, are shown in the table. The variations are indicated in the chart.
The normal diet showed acidity throughout the tract, with considerable constancy at each level. High fat, protein, or carbohydrate variations caused no notable changes, the results falling within the normal ranges.
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