298 Beer, Development of tlie pollen grain and antlier of some Onagraccae. 
2. Absolute Alcoliol. 
Pollen grain = 62 y, 
„ cavity = not measured. 
„ protoplast =16 y. 
Alcoliol always caused great sbrinkage of tlie protoplast. 
VI. Tlie following observations were made upon tbe pollen 
grains in tbe following media. 
1. Tbe st amen was placed in a drop of olive oil and 
tlie pollen carefully teased out witbout coming into 
contact witb tlie air. 
Pollen grain = 68 y. 
„ cavity = 41 )j, 
,, protoplast = 28 y. 
2. Pollen grains teased rapidly into di still ed water and 
immediatly exaniined sbowed a protoplast of 28 y in 
pollen grain 68 y across; very soon bowever tbe 
vacuoles of tbe protoplast enlarged, ruptured tbe 
separating arms and laminae of cytoplasm and ran 
togetlier so tbat tbe protoplast slowly swelled up 
until it quite filled tbe pollen-cavity (42 y). 
3. In 2% cane sugar tlie results were similar to tliose 
in distilled water. 
4. In 5% cane sugar. 
Tbe protoplast for some time maintained its size 
28 to 30 y. Later, bowever in some of tbe pollen 
grains cbanges similar to tliose of 2. and 3. were 
seen but mucli less marked. 
5. In 0,6% Ha CI. 
Tbe protoplast measured ab out 28 y and it remained 
unaltered after a prolonged examination. 
6. In 2% Na CI. 
Protoplast measured only 20 y and was obviously 
plasmolysed. 
Tbe folloAving observations upon 0. biennis may also be 
mentioned. 
I carefully and as rapidly as possible teased out tbe pollen 
grains into a little of tlie mucilaginous fluid wbicb can be squee- 
zed from tbe antber itself. In a pollen grain • measuring 68 y 
and witb a cavity of about 40 y tlie protoplast measured 30 y. 
I tben added a drop of 0,6% Na CI solution to tbe above, 
watcliing tlie effect all tbe time. Tbe pollen grains remained 
unclianged botb in tbeir appearance and in tbeir measure- 
ments. 
In anotlier similar experiment upon anotber bud from a 
different plant tbe measurement botb in tlie antber-juice and in 
tbe 0,6% Na CI solution were: 
Pollen grain =74 y, 
„ caAÜty = 40 y, 
„ protoplast = 30 y. 
