ADDITIONS AND NOTES TO VOL. II. 517 



pancreatic juice in relation to the digestion of starch. We have 

 seen (see p. 514 of this volume) that the pancreatic juice disappears, 

 that is to say, is again absorbed before it reaches the middle of the 

 small intestine, and yet we find that starch is readily converted into 

 sugar below this point. These two properties of the intestinal 

 juice are therefore both directly and indirectly proved. 



(18) Addition to p. 126, line 18 from bottom. Schmidt pro- 

 pounds the question to what extent is the bile decomposed in its 

 passage to the middle of the small intestine ? In order to decide 

 this question, the quantity of the biliary acids precipitated by 

 acetate of lead was compared with the taurine that is already formed, 

 and which was calculated from the amount of sulphur in the fluid 

 freed from an excess of lead : in 100 parts of the intestinal con- 

 tents, there were 2'48 parts of fats and biliary acids soluble in 

 ether, 2'021 parts of insoluble biliary matters (cholic, glycocholic, 

 and taurocholic acids), and 0*143 of taurine. Since the latter is 

 equivalent to 0'622 of pure bile-substance, it follows that almost 

 half of the bile effused into the intestinal canal is decomposed 

 before it reaches the middle of the small intestine. 



(19) Note to p. 126, 6 lines from the bottom. [The faeces have 

 been submitted to chemical examination during the last few months 

 by Wehsarg,* Ihring,t and Marcet.J G.E.D.] 



The following are the most important points in Wehsarg's 

 Thesis : The colour of the normal fseces varies with the food ; on 

 a mixed diet they are of a yellowish-brown tint, on a flesh-diet they 

 are much darker, and on a milk- diet quite yellow. On exposure 

 to the air the colour usually becomes darker, but never red. Very 

 dilute nitric acid, when added in sufficient quantity, always commu- 

 nicates a red colour to the fasces. 



The odour almost entirely disappears on drying, or, at all 

 events, becomes less disgusting. It varies with the kind of food. 

 As a general rule the odour is most intense when the stools follow 

 one another rapidly. 



The consistence seems to depend chiefly on the constitutional 



* Mikroskopische und chemische Untersuehungen der Fseces gesunder 

 erwachsener Menschen. Inaug.-Abhandl. Giessen, 1853. 



t Mikroskropisch-chemische Untersuelmngen menschlicher Fseces nnter 

 verschiedeuen pathologischen Verlialtnissen. Inaug.-Abhandl. Giessen, 1853. 



4 Proceedings of the Royal Society, June 15th, 1854. Vol. 7, p. 153. 



