470 ANDREWS: PROTOPLASMIC STREAMING IN Mucor 
A measurement of the distance traversed in the time given for 
the apical and basal stream would also substantiate this. In the 
second experiment the spores were grown in Io per cent gelatin 
and under the same conditions as the previous experiment. 
A glance at the figures in TABLE I! will show that the total time of 
streaming to the tip in the experiment shown by TABLE II was also 
slightly greater than the time the protoplasm streamed to the base, 
by 714 minutes. An estimate of the time spent in streaming to 
the tip and base, taking into consideration the rapidity of flow of 
the protoplasm, shows that the difference as to time, as is above 
seen, is not very great in this experiment. The observations 
recorded in TABLE 11 were made from plants that were studied 
continuously for about five hours, and when the observations 
were discontinued at 8 Pp. M. the streaming of the protoplasm 
was still going on and could be seen again the next morning. The 
results of TABLES I and 11 in the two preceding experiments were 
also substantiated by numerous other such experiments not 
recorded here. Under natural conditions, however, if any dif- 
ference could be detected in hyphae that were fully active in every 
respect, a slightly greater activity or flow toward the tip or young 
portions would be expected. To prove this would require -. 
interrupted observation from the time streaming first begins 10 
the hyphae of these fungi. The streaming, as above mentioned, 
does not begin as soon as the spore has germinated, but only after 
the hyphae have attained some length. Good streaming hyphae 
were found in many cases after the spore had been sown about 18 
hours, and nearly always 24 to 30 hours were sufficient at the 
optimum temperature to grow hyphae showing active protoplasmic 
streaming. 
It is by no means always the case as Schrite : 
that branching of the young hyphae is necessary for streaming to 
occur. It is true that no streaming of the protoplasm sac aid 
when the filament is very young and entirely filled with granular 
protoplasm. As soon, however, as the filament has increased con- 
siderably in length and before any branches whatever have been 
h 
formed, streaming is often plainly visible. Generally a ah 
r* seems to think, 
tepaming an 
5 
1 
branched rapidly growing filament 
* Schréter, loc. cit. 7, 8. 
