SrupiEs IN POLLEN, WITH SPECIAL REFERENCE TO LONGEVITY 785 
to effect fertilization. As the temperature of liquid air is somewhere near 
—180° C., the resistance shown is very remarkable. 
Corn pollen is not able to withstand such low temperatures. Andronescu 
(1915) mentions the stimulative effect on corn-pollen germination of a 
temperature of from 8° to 14° C. In the storage experiments, there is 
a record of corn pollen which fertilized after forty five hours storage at 
0° C. At —17° C., the pollen was dead after twenty-four hours. It is 
probable, therefore, that it cannot withstand a temperature much below 
freezing. 
Antirrhinum pollen also is able to resist fairly high temperatures, as 
is shown by table 32. Other results, not included in the table, were 
similar. 
TABLE 32. ANntTIRRHINUM POLLEN STORED AT 52° C. 
Time of storage @oninnation Length of 
germ tubes 
d Hours Per cent 
WT FB 0 5 0.b.0:0 6 Se i SRE ee NE dR eN 75 Short 
He PE ea ere PON apes eve ey st at ale gees Save, ateibpcvenchete 75 Short 
1DUDBs o oo boob oc8 6 SS eT es ere lane tat 50 Short 
13-0 Bo o's vob aeias OO eee nn ete Btn ee ia hea 60 Short—medium 
4b Dio.o6 66 Bo CUB OO OOS ee T Cea Tne Seem ae a ae 30 Short 
Ab TB oS. 6 6 0 Ges OOS uN Er gre 10 Short 
115. AB 6.6.5 0° b SG a Sle ee Bae eee ee ne 15 Short 
Altho germination resulted after storage at this high temperature, it 
was weak and most of it abnormal in appearance, the germ tubes being 
short and swelled at the apexes. It is doubtful whether any fertilizations 
would have resulted from pollinations made with this pollen. 
At the time when these experiments were made, the behavior of the pollen 
subjected to the high temperatures impressed certain facts on the mind 
of the author. Death seems to be progressive, with no point of absolute 
distinction between live and dead pollen. Germination became weaker 
and weaker as the duration of subjection to the higher temperature 
increased. This germination was abnormal but there was always the 
uncertainty as to whether the pollen was really alive. Living protoplasm 
is organized, while dead protoplasm is disorganized. Disorganization 
cannot occur quickly but must take place in stages, the rapidity being 
