225 



February 1, 1855. 

 Colonel SABINE, Treas. and V.P., in the Chair. 



The following communications were read : 



I. The reading of Dr. JAGO'S paper, " On Ocular Spectres and 

 Structures as Mutual Exponents," was resumed and con- 

 cluded*. 



IT. " Micro-chemical Researches on the Digestion of Starch and 

 Amylaceous Foods." By PHILIP BURNARD AYRES, M.D. 

 Lond. Communicated by JOHN BISHOP, Esq., F.R.S. Re- 

 ceived January 11, 1855. 



After some general historical remarks on the methods hitherto 

 employed in the investigation of the complicated phenomena of the 

 process of digestion, the comparatively small results obtained by 

 chemical analysis of the contents of the stomach, intestinal canal, and 

 of the evacuations, by Tiedemann and Gmelin, Berzelius, and others, 

 the author proceeded to demonstrate the necessity of a minute ex- 

 amination of the contents of the alimentary canal by the microscope, 

 and such chemical tests as we possess for the determination of the 

 changes of such articles of food as exhibit definite structure. 



In order that we may ultimately arrive at a complete exposition 

 of the phenomena of digestion, he is of opinion that it will be neces- 

 sary to examine, first, the structure of particular kinds of food, 

 then the changes produced in them by cooking, and lastly to trace 

 the changes they undergo at short intervals, through the alimentary 

 canal from the stomach to the rectum. The results of a series of 

 researches of this character on the changes in starch, and starch- 

 containing foods, are presented in this memoir. 



* An abstract is given at p. 208. 

 VOL. VII. 2 A 



