DIGESTION OF FOOD. 815 
the necessity for caution in drawing conclusions about the 
digestive juices as obtained by our present methods. 
The freshest juice obtainable through a recent fistulous 
opening in the pancreatic duct is clear, colorless, viscid, alka- 
line in reaction, and with a very variable quantity of solids 
(two to ten per cent), less than one per cent being inorganic 
matter. 
Among the organic constituents the principal are albumin, 
alkali-albumin, peptone, leucin, tyrosin, fats, and soaps in small 
amount. The alkalinity of the juice is owing chiefly to sodium 
W 
Fie, 269.—Crystals of leucin (Funke). Fic. 270.—Crystals of tyrosin (Funke). 
carbonates, which seem to be associated with some proteid 
body. There is little doubt that leucin, tyrosin, and peptone 
arise from digestion of the proteids of the juice by its own 
action. 
Experimental.—tIf the pancreatic gland be mostly freed from 
adhering fat, cut up, and washed so as to get rid of blood; 
then minced as fine as possible, and allowed to stand in one-per- 
cent sodium-carbonate solution at a temperature of 40° C., the 
following results may be noted: 1. After a variable time the 
reaction may change to acid, owing to free fatty acid from 
the decomposition (digestion) of neutral fats. 2. Alkali-albu- 
min, or a body closely resembling it, may be detected and sep- 
arated by neutralization. 3. Peptone may be detected by the 
use of a trace of copper sulphate added to a few drops of caustic 
alkali, which becomes red if this body be present. 4. After a 
few hours the smell becomes fecal, owing in part to idol, 
which gives a violet color with chlorine-water; while under 
the microscope the digesting mass may be seen to be swarming 
