426 OP FOOD, AND THE DIGESTIVE PROCESS. 



ciple 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 support 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. Perhaps, as Dr. A. Combe remarks, the little support gained from 

 fluid diet, is due to the rapid absorption of the watery part of it; so that the 

 really nutritious portion is left in too soft and concentrated a state, to excite the 

 healthy action of the stomach. Dr. Beaumont also ascertained, that moderate 

 exercise facilitates digestion, though severe and fatiguing exercise 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 has been small, it is of decided benefit. The 

 influence of temperature on the process of solution 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 occa- 

 sion, 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 re- 

 stored for more than half an hour. Hence the practice of eating ice after din- 

 ner, or even of drinking largely of cold fluids, is very prejudicial to digestion. 



450. It is far from being true, however, that according to the older views of 

 the power of the Gastric juice, it 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 consist- 

 ence, 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 aliment- 

 ary 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, towever, having a strong acid reaction. 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 entirely limited to azotized substances; and that it exerts no action whatever 

 either upon starchy, saccharine, or oleaginous matters. Although the change 

 in the starchy particles, which commenced in the mouth, is usually continued 

 in the stomach, yet its continuance is entirely dependent upon the presence of 

 the salivary fluid; being completely checked when, by tying the oesophagus, 

 that fluid is prevented from passing into the stomach. 1 Saccharine matters, 

 being readily soluble in water, do not require the agency of the gastric fluid, 

 for any other purpose than the solution of their investments, whereby they are 

 set free; and it does not appear that it exerts any converting power upon them. 

 So, again, Oleaginous matters are merely reduced to a state of fine division, and 

 are diffused in a state of suspension through the pulpy chyme. The effect of 

 the gastric fluid upon the several kinds of Albuminous matters is to reduce 

 them to a state of complete solution, and at the same time to alter their chemi- 



1 See Frerichs in "Wagner's Haudworterbuch," Art. "Verdauung." 



