OF NATURAL HISTORY. 231 



forty-eight hours, had exerted no folvent power. As the hufks of 

 the feeds refifted the adion of the gaftric juice, he bruifed them, and 

 repeated the experiment. ' Four tubes full of this coarfe flour,' 

 fays he, ' were given to a crow : They remained eight hours in the 

 ftomach, and proved the juftnefs of my fufpicion; for, upon ex- 

 amining the contents, I found above a fourth part wanting. This 

 could arife from no other caufe but folution in the gaftric liquor, 

 with which the remainder was fully impregnated. Another ob- 

 fervation concurred in proving the fame propofition: TJie largeft 

 bits of wheat and bean were evidently much diminiflied : This 

 muft have been owing to the gaftric liquor having corroded and 

 difTolved good part of them, as the nitrous acid, diluted with a 

 ' large quantity of water, gradually confumes calcareous fubftances. 

 I replaced what remained of the feeds in the tubes, and committed 

 them again to the ftomach, wherein they remained, at different 

 intervals, twenty-one hours ; at the end of which period they 

 ' were entirely diflblved; nothing being left but fome pieces of hufk, 

 and a few inconfiderable fragments of the feeds. Wheat and beans 

 floating loofe in the cavity of the ftomach, undergo the fame alte-? 

 ration as in the tubes. When I fed my crows with thefe feeds, I 

 obferved, that, before they fwallowed them, they fet them under 

 their feet, and reduced them to pieces by repeated ftrokes of their 

 long and heavy beaks : And now they digefted them very well ; 

 nay, this procefs was very rapid in comparifon of that which took 

 place within the tubas. But, when the birds, either from excef- 

 ■ five hunger, or violence, fwallowed the feeds entire, the greateft 

 part of them paffed out entire at the anus, or were vomited. We 

 cannot, therefore, be furprifed, that the gaftric juice could not dif- 

 folve them within the tubes, fince it was incapable of effecting 

 this procefs within the cavity, of the ftomach, where its folvent 

 power is far fuperior.' 



Similar; 



