Natural History. 197 



16. Observations on the Contents of the Digestive Canal in the Foetus 

 of Vertebral Animals, by MM. Prevost and Royer. — An abstract is 

 contained in the last volume of this Journal, p. 169, of a paper 

 by these philosophers on digestion, in which they endeavoured to 

 establish that that function resulted from the alternate action of 

 soda and muriatic acid, secreted by the alimentary canal upon the 

 food. Their object in a second paper or note, the abstract of 

 which follows, was to examine the subject as connected with that 

 time in the existence of the animal, during which the organs were 

 forming, or beginning to act. This examination it appears con- 

 firmed their original views. 



The chick in the egg was first subjected to examination. It was 

 only on the ninth day of incubation that the organs were in such 

 a state as to permit of the fluid in the stomach and intestines being 

 collected, only a few drops then being obtained from many indi- 

 viduals. At this time the crop or first stomach, the glandular 

 stomach and the gizzard contained a transparent liquid, extending 

 into threads between the fingers, and slightly alkaline ; tested by 

 acids, alcohol, and corrosive sublimate, it, from the precipitates 

 formed, appeared to be abundant in albumen. The liquid of the 

 intestines appeared to be of the same kind, but was in too small 

 a quantity to be easily examined. The waters of the amnios gave 

 much less abundant precipitates ; they were clear, slightly yellow, 

 and not extensible into threads between the fingers. The waters 

 of the allantoides contained no albumen, and were very clear. 



On the thirteenth and fourteenth day the liquid of the glandu- 

 lar stomach had increased in quantity, it contained much more al- 

 bumen, and coagulated by heat : that portion which was in con- 

 tact with the membrane containing it, was white, and had the ap- 

 pearance of albumen precipitated by an acid, and in fact when 

 put upon test paper, it sensibly reddened it. On opening the giz- 

 zard, it was seen that the acid had flowed from the glandular 

 stomach into its cavity, by the manner in which the precipitate 

 was formed ; abundant near the cardia, but very slight towards 

 the pylorus. 



The waters of the amnios coagulated by heat, and were slightly 

 alkaline to test paper. Those of the allantoides were slightly 

 turbid, from the presence of a portion of crystalline uric acid. 



On the seventeenth day the changes were complete. The fluid 

 of the crop was the same, but that of the glandular stomach and 

 gizzard was entirely coagulated, and decidedly acid. Particles of 

 albumen were found in the intestines, carried there by the peris- 

 taltic motion ; their surface was of a fine green colour. There 

 was also found a substance containing globules, and of a yellowish 

 gray aspect ; it was a mixture of mucus and albumen. The waters 

 of the amnios were denser than before. Those of the allantoides 

 were of a yellowish white, slightly acid whilst warm from the sac, 



