

STOMACHAL DIGESTION. 241 



rest of the intestinal tube, produces gases in considerable 

 quantity; chiefly carbonic acid and nitrogen. Thus these 

 do not always arise from fermentation but really come from 

 the blood, and are evolved, for instance in all cases of para- 

 lysis of the digestive tube, whether or not it contains ali- 

 mentary substances; they may thus be suddenly produced 

 under the influence of moral emotions, and be as quickly 

 reabsorbed. 



Cl. Benard has recently called the attention of physiolo- 

 gists to similar facts. " In the lung," he says, " and on the 

 cutaneous surface, these gases may be exhaled simply as a 

 result of simple interchange between the exterior and the 

 interior medium ; but in the intestine, in which normally no 

 air exists, the exhalation of gas must take place by means of a 

 different mechanism. The nervous system has, probably, some 

 influence in producing these gases, for I have known them 

 to appear in large quantities after operations performed upon 

 the spinal cord. The eliminated gaseous substances are 

 generally those which can be absorbed. Hydrogen, how- 

 ever, which is not sensibly absorbed, is sometimes exhaled 

 in various quantities, as shown in experiments by Regnault 

 and Reiset." 1 



The conditions under which the fluids of the stomach are 

 secreted are quite peculiar. Thus mucus is readily pro- 

 duced when the stomach is fasting or fatigued, or when 

 occupied by a foreign body which is not alimentary; a 

 sponge, introduced into the stomach, imbibes a mucus 

 which is sometimes strongly acid (gastric juice without pep- 

 sin) and must not be confounded with the real gastric juice, 

 as was formerly done. 



The real gastric juice is secreted only under the influence 

 of an excitant of a peculiar character, an alimentary sub- 

 stance ; or, in other words, secretion takes place chiefly when 

 the aliment is an albuminoid (muscular flesh, fibrine, white 

 of egg), that is to say an aliment which essentially requires 

 the action of the gastric juice. Under these circumstances 

 the coat of the stomach in all those parts which come in 

 contact with a suitable excitant, becomes red and turgescent, 

 and there ensues an abundant secretion of the gastric juice, 

 which soon transforms the albuminoid aliment into albumi- 

 nose. These facts show that the secretion of the gastric 



1 Cl. Benard, " De la Physiologie G6n6rale." Notes, p. 290, 



1872. 



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