Form of Hormidium flaccidum , A. Braun. 533 
during the first part of the period of desiccation. It is a more difficult 
matter to elucidate the converse process, an absorption of granules, which 
the curves indicate (cf. Fig. 5), after the proportion of living cells with 
granules has reached its maximum (e. g. after nine weeks in Experiment II), 
for even at this time the granules in a considerable number of the cells are 
small and scanty. Nevertheless, estimates of the proportion of living cells 
with numerous granules, though necessarily of an approximate nature, 
showed an increase during the first five weeks of Experiment II and a sub- 
sequent decrease, corresponding roughly with the similar variation in the 
proportion of living cells with granules shown by the curve (Fig. 5, a 2 ). 
The falling off in the proportion of living cells with granules, which 
occurs in the latter part of both experiments, might be attributed to the 
death of granular cells. The latter were in fact frequently found among 
the dead. But in many cases at least, the increase in the number of dead 
cells was not nearly sufficient to account for the decrease in the above ratio. 
Thus, between the sixty-second and the seventy-third day of Experiment II, 
the percentage of granular living cells to total living cells decreased from 
ninety-five to eighty-three. The percentage of dead cells to total cells 
increased during the same period from forty-six to fifty-five. If this had 
been entirely due to the death of granular cells, there would only have 
resulted a decrease of 1 per cent, of granular living cells. Therefore an 
increase in the number of clear cells must be supposed to have occurred. 
This conclusion is borne out by the appearance of 40 per cent, clear cells in 
filaments, previously recorded as completely granular, between the fourth 
and sixth weeks of Experiment I. 
The occurrence of a second maximum after twenty weeks in Experi- 
ment II, as well as the continued prevalence of granules in a large proportion 
of the living cells after the attainment of the first maximum (at the end of 
six to nine weeks), seems to indicate that the production of granules may 
extend over a long period, if the desiccation is gradual and the temperature 
and sunshine adequate. 
A comparison of Experiments I and II shows that filaments which 
become stocked with large and abundant granules (as in Experiment II) 
are capable of much longer resistance to drought than filaments in which the 
granules disappear or become small and scanty (as in Experiment I). On 
the other hand, the continual dying of abundantly granular cells suggests 
that the granules themselves do not preserve the cells, but are indicative 
only of certain resources which the latter possess. 
As described on p. 525, granules are very commonly present in 
normally growing cells, and it is therefore probable that they are primarily 
a by-product of metabolism. Results obtained from experiments on 
nutrition confirm this view. Thus granules are not formed in filaments, 
which, though growing under otherwise normal conditions, are deprived of 
