OTHER SUBSTANCES EMPLOYED. 501 



that renders the solitary use of a nutritive substance (as 

 starch, gum, or sugar) less favourable to assimilation, and 

 to the reparation of the losses which the human body under- 

 goes. Opium, which is not nutritive, is employed with 

 success in Asia, in times of great scarcity; it acts as a 

 tonic. But when the matter which fills the stomach can 

 be regarded neither as an aliment, that is, as proper to be 

 assimilated, nor as a tonic stimulating the nerves, the 

 cessation of hunger is probably owing only to the secretion 

 of the gastric juice. We here touch upon a problem of 

 physiology which has not been sufficiently investigated. 

 Hunger is appeased, the painful feeling of inanition ceases, 

 when the stomach is filled. It is said that this viscus 

 stands in need of ballast; and every language furnishes 

 figurative expressions, which convey the idea that a mecha- 

 nical distension of the stomach causes an agreeable sen- 

 sation. Recent works of physiology still speak of the 

 painful contraction which the stomach experiences during 

 hunger, the friction of its sides against one another, and 

 the action of the gastric juice on the texture of the diges- 

 tive apparatus. The observations of Bichat, and more par- 

 ticularly the fine experiments of Majendie, are in contra- 

 diction to these superannuated hypotheses. After twenty- 

 four, forty-eight, or even sixty hours of abstinence, no 

 contraction of the stomach is observed ; it is only on the 

 fourth or fifth day that this organ appears to change in a 

 small degree its dimensions. The quantity of the gastric 

 juice diminishes with the duration of abstinence. It is 

 probable that this juice, far from accumulating, is digested 

 as an alimentary substance. If a cat or dog be made to 

 swallow a substance which is not susceptible of being 

 digested, a pebble for instance, a mucous and acid liquid 

 is formed abundantly in the cavity of the stomach, some- 

 what resembling in its composition the gastric juice of the 

 human body. It appears to me very probable, that when 

 the want of aliments compels the Ottomacs and the inha- 

 bitants of New Caledonia to swallow clay and steatite 

 during a part of the year, these earths occasion a powerful 

 secretion of the gastric and pancreatic juices in the digestive 

 apparatus of these people. The observations which I made 

 on the banks of the Orinoco, have been recently confirmed 



