552 
ADRIAN J. PIETERS 
Table XI 
Series I. Saprolegnia ferax. Record of Table X Arranged in Two Groups According 
to the Number of Oogonia Per Square of 25 Square Millimeters. 
Weights in Milligrams 
2 
3 
4 
5 
No. 
Number of Oogonia 
Weight in 7 Days 
Weight in 48 Days 
Increase in Weight 
Group I: 
2 
16 
.002 
.005 
X2.5 
6 
18 
.0035 
.007 
X2 
7 
28 
.0054 
.010 
Xl.85 
II 
28 
.0023 
.007 
X3 
3 
30 
.003 
,011 
X3.3 
4 
34 
.004 
10 
36 
.002 
.0066 
X3.3 
Group II: 
6m 
41 
.0044 
.033 
X7.5 
42 
.004 
.033 
X8 
43 
.005 
.036 
X7 
12 
43 
.003 
9m 
50 
.005 
.044 
X9 
9 
51 
.006 
.020 
X3.3 
8 
53 
.0054 
.013 
X2.5 
when the weights of the myceha forty-eight days old are compared. 
Number 12 has the one disturbing record in this series. With a small 
weight, it combines a rather large number of oogonia. From the 
weight of mycelium as well as from the composition of the food, 
it was to be expected that this lot would appear in a group with 
numbers 2, 3, 10, and 11. The explanation of the peculiar behavior 
of this lot doubtless lies in the fact that no sporangia were produced in 
haemoglobin. As has already been shown, the suppression of spo- 
rangia, in a solution of this sort, reacts very favorably on the formation 
of oogonia, but why no sporangia were formed in this case it is im- 
possible to say. A study of the record in Table XI would seem to 
show an agreement between weight of mycelium and the number of 
oogonia produced. But this is true only as showing a trend toward a 
minimum food requirement. In group I, for example, o.i percent 
peptone is clearly too poor a food to produce vigorous mycelium and 
the addition of sucrose alone does not add to the vigor of growth. 
When, however, salts are added, or higher concentrations of peptone 
used, the number of oogonia at once approaches that of the lower 
numbers in the second group. The separation of the groups along 
the line between 36 and 41 oogonia is, of course, arbitrary and only 
