1914] BARTHOLOMEW—DIASTASE IN RED ALGAE 139 
nature of the extracts, solutions of this concentration were quite 
viscous. In most cases the viscosity would about equal that of a 
75 per cent solution of glycerine and water. That a check might 
be had as to the time required for action and as to the final results, 
solutions of commercial diastase were also used. The solutions 
were of the same concentration as those of the algal extracts and . 
were applied and tested in the same manner in every case. Both 
Eimer and Amend’s and Merck’s diastase were used, with no 
apparent difference in the results. 
4. STARCH PASTE 
Corn starch was used in all experiments. The paste used was 
made by adding 0.25 gm. of starch to 100 cc. of water and boiling 
6 minutes. The boiling, though done slowly and in an Erlenmeyer 
flask plugged with cotton, probably caused 1o per cent of the 
water to be vaporized. No water was added to make up for this 
loss. New solutions of paste were made for each series of experi- 
ments: 
5. CONTROL MEASURES 
To determine as far as possible all sources of error, the following 
control measures were taken: 
a) The “A, B, and C” parts of Fehling’s solution were mixed 
Just preceding each series of experiments. 
6) Tubes of untreated paste were tested each time and in the 
same manner as those tubes containing the paste plus the extracts. 
: c) To detect any error due to the presence of an active agent 
* the distilled water, tubes of the paste were treated each time 
with distilled water only and tested in the regular manner. 
: 4) Toluol was used as a sterilizing medium, except in the Van 
Tieghem tests, in which 10 per cent alcohol was used. 
e) All containers and instruments were carefully sterilized with 
# strong solution of potassium bichromate and sulphuric acid. 
6. TEST METHODS 
A. Digestion in test tubes 
The proportionate amounts of starch, algal extracts, commercial 
and distilled water used in each series of tests were as 
ollows: 
