272 Wisconsin Academy of Sciences, Arts, and Letters. 
ing commercial pepsin digested the fastest, that of the tube in 
which no enzyme had been placed the slowest. The test with di¬ 
lute copper sulphate in an alkaline solution showed the presence of 
proteoses and peptoses in tubes (1) and (2) but not in tube (3). 
The contents of the stomach of the perch, while distinctly acid 
to litums, was so small in quantity that it would require frac¬ 
tions of drops in order to titrate for the acidity. Such an ex¬ 
periment was not performed. 
Intestinal Digestion 
With proteins. Three test tubes were filled, respectively with 
(1) 0.2 gram egg albumen and 20 drops of glycerine extract of 
the intestine; (2) 0.2 gram egg albumen and 20 drops commercial 
pancreatin solution; (3) 0.2 gram egg albumen. All three were 
filled with a 1% solution of sodium carbonate, and placed in a 
bath of 40° C. for 35 minutes. The commercial pancreatin di¬ 
gested the fastest and the contents of the tube in which no enzyme 
was placed, the slowest. The test with dilute copper sulphate 
showed the presence of proteoses and peptoses in tubes (1) and 
(2) but not in tube (3). 
With cane sugar. Three test tubes were set up, containing, 
respectively: (1) 10 drops intestine extract and 2 cc. cane sugar 
solution; (2) 10 drops commercial pancreatin solution and 2 cc. 
cane sugar solution; (3) 2 cc. cane sugar solution. These were 
half filled with a 1% solution of sodium carbonate, and placed 
in a bath at 35° C. for 45 minutes; 2 cc. of Fehling’s solution 
were then added to each, and all were allowed to stand for twen¬ 
ty-four hours. At the end of that time the Fehling’s solution 
was completely reduced in the test tube containing commercial 
pancreatin, showing that the cane sugar had been inverted. A 
slight inversion had taken place in the tube containing glycerine 
extract of the intestine, and none at all in the test tube in which 
no enzyme had been placed. 
Bile. The bile of the perch was very active in emulsifying 
oils, one drop forming a thick emulsion with 20 drops of olive oil. 
Discussion and Conclusions 
The pickerel, whose diet in the adult stage consists almost 
wholly of fish (Pearse, 1915), apparently has no enzyme adapted 
to the inverting of sugars, an essential function of the digestive 
