472 ANDREWS: PROTOPLASMIC STREAMING IN MUCOR 
of the filaments protruding from the water, for in those spores 
that had germinated and whose filaments had not grown out of 
the hanging drop of sugar solution the streaming was absent. In 
every case of the many specimens examined streaming always began 
just as soon as a filament protruded from the solution into unsatu- 
rated air; and during the whole active life of the fungal filaments 
the velocity of protoplasmic streaming would be accelerated by 
artificial conditions, as the length of the filaments outside the drop 
became greater and the transpiring surface was increased. These 
specimens were kept growing in the glass cells for five days, at 
the end of which time the filaments had attained a great length, 
and in these rapid streaming was visible. Sporangia were also 
formed in both cultures. 
In another experiment the spores of the fungi were grown under 
the cover glass on an ordinary slide in a 5 per cent solution of sugar 
or at times in water and the filaments allowed to grow from under 
the cover glass into the warm air of the constant temperature room 
or warm chamber. As before, so long as the filaments were com> 
pletely submerged no streaming occurred, but as in the preceding 
experiment, as soon as the filaments emerged from the cover glass 
into the warm dry air an active streaming of the protoplasm com- 
menced. In other experiments the fungal filaments were caused 
to grow from under the cover glass directly into a drop of water: 
When the water outside the cover glass was removed, streaming 
began immediately and was slow or rapid according as the amount 
of surface of the fungal filaments thus exposed to the dry air was 
small or large. The movements thus induced to the point where 
transpiration was occurring continued visible for a long time, oF 
until practically all the movable part of the protoplasm bias 
crowded as nearly as possible into the transpiring parts. en 
this occurred the vacuoles, which before were more oF less elongated 
parallel to the long axis of the filaments, were now S° crowae 
together and were so strongly compressed that their long wo 
was generally transverse to the filament. When water was agaltl 
placed on any filament or filaments outside the cover glass from 
which it had been removed, a streaming movement immediately 
began away from the point at which such addition wa c 
This return movement continued, by this absorption, until equi 
