GASTRIC DIGESTION. 165 



may be drawn from his researches. It seems to be a general rule, that the 

 flesh of wild animals is more easy of digestion than that of the domesticated 

 races which approach them most nearly. This may, perhaps, be partly 

 attributed to the small quantity of fatty matter that is mixed up with the flesh 

 of the former, whilst that of the latter is largely pervaded by it. For it ap- 

 pears from Dr. B.'s experiments, that the presence in the stomach of any 

 substance which is difficult of digestion, interferes with the solution of food 

 that would otherwise be soon reduced. It seems that, on the whole, Beef is 

 more speedily reduced than Mutton, and Mutton sooner than either Veal or 

 Pork. Fowls are far from possessing the digestibility that is ordinarily im- 

 puted to them ; but Turkey is, of all kinds of flesh except Venison, the most 

 soluble. Perhaps the average period required for the digestion of an ordinary 

 meal, and the complete emptying of the stomach, maybe roughly estimated 

 at from 3 to 4? hours. Dr. Beaumont's experiments further show that bulk 

 is as necessary for healthy digestion, as the presence of the nutrient principle 

 itself. This fact has been long known by experience to uncivilized nations. 

 The Kamschatdales, for example, are in the habit of mixing earth or saw- 

 dust with the train-oil on which alone they are frequently reduced to live. 

 The Veddahs or wild hunters of Ceylon, on the same principle, mingle the 

 pounded fibres of soft and decayed wood with the honey on which they feed 

 when meat is not to be had ; and on one of them being asked the reason of 

 the practice, he replied, " I cannot tell you, but I know that the belly must 

 be filled." It is further shown by Dr. B., that soups and fluid diet are not 

 more readily chymified than solid aliment, and are not alone fit for the sup- 

 port of the system; and this, also, is conformable to the well-known results of 

 experience; for a dyspeptic patient will frequently reject chicken-broth, when 

 he can retain solid food or a richer soup. Dr. Beaumont also ascertained, 

 that moderate exercise facilitates digestion, though severe and fatiguing exer- 

 cise retards it. If even moderate exercise be taken immediately after a full 

 meal, however, it is probably rather injurious than beneficial ; but if an hour 

 be permitted to elapse, or if the quantity of food taken have been small, it 

 is of decided benefit. The influence of temperature on the process of solu- 

 tion is remarkably shown in some of Dr. B.'s experiments. He found that 

 the gastric juice had scarcely any influence on the food submitted to it, when 

 the bottle was exposed to the cold air, instead of being kept at a temperature 

 of 100. He observed on one occasion, that the injection of a single gill of 

 water at 50 into the stomach, sufficed to lower its temperature upwards of 

 30 ; and that its natural heat was not restored for more than half an hour. 

 Hence the practice of eating ice after dinner, or even of drinking largely of 

 cold fluids, is very prejudicial to digestion. 



116. It is far from being true, however, that (according to the older views 

 of its power) the Gastric juice is capable of acting upon all the nutritive 

 components of the food. The mistake probably arose from the reduction 

 to which these matters are subjected in digestion, the alimentary bolus being 

 completely disintegrated, and its particles saturated with the fluids of the 

 stomach, so that the whole forms a homogeneous liquid of pultaceous con- 

 sistence, to which the name of chyme is given. This chyme will of course 

 vary greatly in its composition, according to the proportion of the different 

 alimentary substances that have entered into the composition of the food; 

 and its appearance, also, is far from uniform, being sometimes like gruel, 

 but sometimes more creamy, always, however, having a strong acid reac- 

 tion. All the more recent and accurate experiments of those who have 

 studied the chemistry of digestion, lead to the conclusion, that the solvent 

 powers of the Gastric juice are chiefly exerted upon azotized substances ; and 

 that its action is comparatively slight upon starchy, saccharine, and ole- 



