Form of Hormidium Jlaccidum , A. Braun. 531 
less draught through the apparatus of the second experiment than through 
that of the first experiment. Direct evidence of the abundant humidity 
of the air inside the glass bowl was furnished by the condensation of 
drops of water on the inside of the covering glass during the first two or 
three weeks of this experiment. The process of desiccation to which the 
Hormidium was subjected in Experiment II was therefore much more 
gradual than in Experiment I, and this was shown by the soil remaining 
obviously damp during the first fortnight. 
At intervals of about a week, the size and frequency of the granules in 
the cells were noted and records made of (i) the proportion of the living 
cells containing granules, and (ii) the proportion of dead cells. The results 
obtained during the course of the first and second experiments are shown 
in Tables I and II, respectively, and are plotted as curves in Fig. 5. 
The question arises as to what reliance can be placed on individual 
observations. The chief errors may be conveniently divided into those due 
to observation and those due to variability among the filaments. To reduce 
the first to a minimum, great care was taken to secure good definition under 
the microscope, and a high magnification was used. The second were far 
more difficult to cope with. Filaments selected from different parts of an 
area of a few square inches were very variable, as were also, though to a less 
degree, even those within the limits of very small regions. An effort was 
made on each occasion to examine filaments representing the condition of 
the patch as a whole, and in addition records were made of a large number 
of cells ; usually between a, 000 and 3,000. 
To obtain some idea of the accuracy of the readings, counts were made, 
in two instances, on successive days ; the variation of the readings on either 
day from the mean value, obtained by compounding the two days’ counts, 
is shown in Table III below : 
Table III 
Total 
Cells. 
Dead 
Cells. 
Dead 
Cells 
to 
Total 
Cells. 
% 
Living 
Cells. 
Granular 
Living Cells . 
Gran. Liv. Cells 
to 
Total Liv. Cells . 
% 
March 1 1 
2263 
149 
✓O 
7 
2134 
Mi 5 
66 
March 13 
3368 
365 
10 
3°°3 
1611 
53 
Compounded value for 
Mar. 1 1 and Mar. 1 3 
5631 
5 H 
9 
5137 
3026 
59 
Greatest deviation 
from mean value 
2 
7 
March 20 
2609 
203 
8 
2414 
1621 
67 
March 21 
2119 
280 
13 
1837 
1397 
6 
Compounded value for 
Mar. 20 and Mar. 21 
4728 
483 
10 
4 2 5 i 
3018 
7 i 
Greatest deviation 
Irom mean value 
3 
5 
