226 
Notes. 
The ground pollen after a few hours’ exposure to the solvent was 
filtered off and the filtrate tested by allowing it to remain in contact 
with cane-sugar in solution or starch-paste of i per cent, strength for 
some hours. The reducing sugar was estimated by titration with 
Fehling’s solution. Details of the various experiments made are 
given at some length in the paper. 
Diastase was by this method prepared from the pollen of Liliurn , 
Helleborus, Helianlhus, Gladiolus. Anemone , Antirrhinum , Tropaeolum , 
Pelargonium, Crocus, Brownea, Alnus, Tulipa , and Clivia. It is very 
widely distributed, very few pollens examined yielding no result. 
Invertase was found in the pollen of Helleborus , Narcissus, Richardia , 
Liliurn, and Zamia. 
During the germination of the pollen the quantity of both enzymes 
was found to be considerably increased ; in some cases four or 
five-fold. The difficulty of extraction was greater in the case of the 
ungerminated grain, the thin-walled pollen-tube yielding it to the 
solvent fairly easily. The facility of extraction was shown, however, 
not to be the explanation of the greater activity of the latter extract, 
but a definite increase in amount was made evident, the increase being 
generally greater when the tubes were grown in a nutritive fluid than 
when they were cultivated in distilled water. 
In one case the increase was found to be preceded by an initial 
diminution, which lasted only till the tube was about four or five 
times the length of the diameter of the pollen-grain. 
When the power of germination of the grain was becoming feeble, 
which usually took place about three weeks after collection, the 
amount of enzyme contained in the pollen was very considerably 
diminished. 
Further experiments were carried out to trace the changes in the 
contents of the grains and tubes as the germination proceeded, and to 
see what was taking place in the cells of the style during the same 
period. 
The contents of the pollen-tube were generally granular, the proto- 
plasm showing streaming movements. Besides the granularity of the 
latter, however, larger refringent granules were observed towards or 
actually at the tip of the tube, which were being continuously or 
intermittently extruded into the culture-fluid. In one case (in 
Narcissus) this extension was observed to take place through a pore 
with well-defined lips at the tip of the tube. The granules so extruded 
