Experimental researches on the food of animals, and the fattening of cattle : with remarks on the food of man, based upon experiments undertaken by order of the British Government / by Robert Dundas Thomson.

  • Thomson, Robert Dundas, 1810-1864.
Date:
1846
Catalogue details

Licence: Public Domain Mark

Credit: Experimental researches on the food of animals, and the fattening of cattle : with remarks on the food of man, based upon experiments undertaken by order of the British Government / by Robert Dundas Thomson. Source: Wellcome Collection.

Provider: This material has been provided by the National Library of Medicine (U.S.), through the Medical Heritage Library. The original may be consulted at the National Library of Medicine (U.S.)

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    Experi- ments. Weight of Chloride of silver. Weight of Chlorine. Weight of Hydro- chloric Acid. 1 2 3 7-81 7-17 7-97 1-95 1-79 1-99 2-00 1-84 2-04 The difference between the first and second experi- ments indicated the amount of chlorine in union with ammonia. In the third experiment the potash displaced the ammonia, and hence the amount of chlorine was the same in the first and third experiments. I there- fore infer that no free hydrochloric acid was present. Hence it appears probable that this acid is produced at the expense of the sugar or starch of the food, and it appears doubtful if any considerable quantity of acid is secreted, as is generally imagined, from the coats of the stomach. Corvisart tells us, that in a case where there was an aperture in the stomach the contents of that or- gan during digestion were neutral; and I have found the contents of the stomach of a sheep during digestion of grass, and several hours after the food had been in- troduced, without either an acid or alkaline reaction. A strong argument, however, against the hydrochloric acid theory of digestion is derived from the circum- stance of the food containing, in many instances, but an insignificant quantity of chlorides, a considerable portion of which is again thrown out with the dung. Hay made from rye grass, for example, contains often merely a trace of chlorine, while in barley, and other kinds of grain, it is often entirely absent. Now as it is obvious that the hydrochloric acid, if any were present in the stomach, must be originally derived from the food, the absence of such a constituent in many kinds of food renders its disengagement in a free state in the 3*