[Vor. 8 
22 ANNALS OF THE MISSOURI BOTANICAL GARDEN 
added the same amount of .5 per cent mycelial extraction ob- 
tained from mats of the fungi grown on potato decoction. Then 
the mixture was incubated at 29-30? C. for 4 hours when the 
sugar determinations were made. 
The second part of table vir, below the horizontal line, repre- 
sents & repetition of most of the work in the first part of the 
table. From the experiments it is inferred that the diastatie 
activity of the strain P4 is notable and beyond that of the re- 
maining strains. Bl is next in order of efficiency. The results 
obtained with P1 and H are rather similar, and follow B1. Dias- 
tatic efficiency of P7 is the least of all. This result is confirm- 
atory of the cultural experiments. No definite conclusion may 
be drawn for B3 owing to the lack of data, but so far as the 
present experiment indicates the activity of the strain is rather 
striking and stands above that of P1, H, and P7. 
Furthermore, this study was repeated several times with the 
use of extractions obtained from different cultures or cultures of 
different ages. In all cases, with the exception of a minor modi- 
fication, those relationships mentioned above have proved rather 
constant, and no marked variation was noticed in any of the 
results. These results were also verified by using the alcohol 
precipitate of mycelium extractions. 
comparative study of the enzyme from the original as 
contrasted with the reisolated strains was also made. P1 and 
P4 were isolated from sclerotia on potato tubers obtained from 
experimentally infected plants (see inoculation experiment No. 
5). The original strain P1 was used for comparison. The 
result obtained after 5 hours is shown below: 
TABLE IX 
DIASTATIC ACTIVITY OF ORIGINAL AND REISOLATED STRAINS 
P1 Reisol. P1 Reisol. P4 
Reducing sugar (mgs.) 4.78 14.13 15.38 
It appears that the diastatic activity of the reisolated strains 
of P1 and P4 is 3 times as great as that of the original P1. From 
