482 ANDREWS: PROTOPLASMIC STREAMING IN Mucor 
were grown in a 10 per cent solution of gelatin. Under favorable 
conditions this medium produced large actively streaming speci- 
mens. The various fungi behaved in this 10 per cent solution of 
gelatin in the same way when subjected to artificial conditions 
to produce or suppress transpiration, as they did in the solution 
of cane sugar. For example, when the streaming of Mucor Mucedo 
and WM. stolonifer had been stopped in a saturated air and the 
plant was then placed over a 20 per cent solution of glycerin, the 
streaming began and moved rapidly to the exposed tips at first 
but gradually became slower and then stopped in 50 minutes. 
This was the average time required under such conditions, which 
will be seen to be a somewhat shorter time than when the fila- 
ments grown in a cane sugar solution were placed over a 20 per 
cent solution of glycerin. It was probably partly due to the 
lack of easily available water in the glycerin medium so that 
transpiration could not continue so long. When the spores were 
grown in a gas chamber and saturated air drawn through, the 
streaming ceased, but began again when dry air was pas 
through the cell. The velocity of streaming was dependent on 
the dryness of the air as prepared in the apparatus shown in FIG. I. 
iS Weed tente Goa: rie WRG 
o3 a eam se ae 
aoe ey 
mes 
Fic. 4. Part of a filament of Mucor stolonifer partially collapsed by excessive tran- 
spiration. XX 400. 
In all the experiments, when transpiration had proceeded too far 
the protoplasm was drawn wholly or partly away from the cell 
wall and gave the appearance shown by FIG. 4. In such cases as 
in FIG. 4, if moist air was readmitted, the protoplasm in a short 
time resumed its natural position and streaming recommenced. 
EXPERIMENTS WITH ETHYL ETHER 
When the same specimen as used above, whose protoplasm 
stopped in 50 minutes over 20 per cent glycerin, was laid over 
a cell containing 20 per cent glycerin to which a 4 pet cent 
solution of ether had been added, streaming began again, more 
