1914] BARTHOLOMEW—DIASTASE IN RED ALGAE 145 
might also act-as a synthetic agent in forming the grains in ques- 
tion. BELzuNG? found that in some species the younger the grains 
the more nearly they came to giving the normal blue color reaction 
when treated with iodine. Hence, if this enzyme does act syn- 
thetically, it appears that, in some cases at least, the action is just 
the reverse of that which takes place in some of the higher plants, 
for example, in Piswm sativum, in which the erythrodextrins are 
formed first, the amylases not appearing until the grains are almost 
mature. 
The difference in rate of amylolytic action between the algal 
extract and the commercial diastase is very noticeable. This is 
already indicated in tables I-IV. This variation may have been 
due to difference in concentration. The algal extracts were known 
to be far from pure, and it was for this reason that solutions of 
rather high concentration were applied to the starch paste. Table 
V indicates that there is also considerable dissimilarity in digestive 
power between the algal extracts themselves. Here again is the 
possibility that this may be attributed to an inequality in purity, 
for the extracts did not all present the same degree of difficulty 
in filtration. However, the explanation is hardly to be looked for 
in this direction, for although A gardhiella and Polysiphonia extracts 
were more difficult to filter than was the Ceramium extract, yet the 
two former completed amylolysis in 6 days, while the latter required 
9 days under the same conditions, as is shown in table V. 
As a result of recent experiments, ACHALME and BRESSON” 
maintain that diffusion is an important factor in the rate of enzy- 
matic action. They found that an increase in viscosity of the solu- 
fon meant a like decrease in the rate of action of invertase upon 
Saccharose, They also maintain that this is true for emulsin, trypsin, 
and for organic oxidases. As has been said, the viscosity of the 
algal extracts would about equal a 75 per cent solution of glycerine 
m water. That this condition influenced the amylolytic action 
os Sooo E., Recherches morphologiques et physiologiques sur l’amidon et 
€ chlorophylle. Ann. Sci. Nat. Bot. VII. 5:223-228. 1887. 
ac , P., and Bresson, M., Influence de la viscosité du milieu sur les 
actions-diastasiques, Compt. Rend. 152:1328-1330. 1911; also Du réle de la vis- 
Cosité dans les variations de V’action de Vinvertine suivant les concentrations en 
Saccharose, pt. Rend. 152:1420-1422. 1911. 
