[Vor. 3 
498 ANNALS OF THE MISSOURI BOTANICAL GARDEN 
Action on albumin, casein, legumin, and peptone.—The pro- 
teolytie action of the enzymes of the sporophoral and mycelial 
dispersions was tested by means of various substrates, under 
acid, alkaline, and neutral conditions. One per cent solutions 
of albumin, casein as such, as well as in the form of com- 
mercial *nutrose," legumin, and peptone were prepared. 
Casein and legumin were dissolved in N/10 NaOH. Albumin 
was also used in the form of Mett’s tubes. 
To determine the tryptic action the biuret test was em- 
ployed. In testing for peptone by the biuret test it is neces- 
sary to get rid of the native proteins, since these give a 
purplish blue coloration with alkaline copper sulphate, the 
purple blinding the fainter pink test for peptone. In order 
to do this ammonium sulphate is usually added in crystalline 
form to precipitate the higher proteins. The precipitate, 
however, is generally in such finely divided particles that it 
will not filter out with the filter papers commonly used. To 
overcome this difficulty the solution was filtered through bone 
black to remove the precipitate. The question arose whether 
the bone black might not absorb the peptone, and tests were 
made as follows: To a few cubic centimeters of 1 per cent 
casein solution was added a small bit of Witte peptone. 
Crystals of ammonium sulphate were added to precipitate the 
casein. After filtering through bone black the clear filtrate 
gave a pink color with sodium hydroxide and dilute copper 
sulphate. 
The tryptophan test was employed in testing for the action 
of erepsin. Wherever a test for tryptophan was given, higher 
proteins being used as a substrate, there was a demonstration 
of tryptic action as well. The tryptophan test is the produc- 
tion of a pink color after the addition of a few drops of glacial 
acetie acid and then a few drops of strong chlorine water. 
Experiments were set up using 10-сс. portions of Ше above- 
mentioned substrates in tubes. Two cubic centimeters of the 
enzyme dispersions were added to each tube, except the water 
eontrols. 'Toluol was used as an antiseptic. Each substrate 
was set up in series of neutral, acid, and alkaline cultures, 
the acidity and alkalinity being approximately N/200. 
