4 071 the Action of the Pollen of Plants, 



object. His style is somewhat obscure, as he does not well 

 distinguish between the pollen itself, which he calls globules, 

 and the particles contained in, and ejected from, the pollen ; 

 but his meaning is sufficiently obvious to prevent any mistake 

 respecting them. Fig. 1. represents 

 the pollen of the mallow ejecting the 

 particles, as seen with his third mag- 

 nifier ; fg. 2. represents one grain of 

 pollen in the act of ejection, as seen 

 with his highest magnifier. 



Mr. Needham asserts that the 

 pollen should be fresh gathered; 

 but this is not necessary, as Mr. 

 Brown has proved. He also says that 

 the act of ejecting the particles continues only a few seconds. 



This maybe true 

 with the pollen 

 gathered in the 

 summer months: 

 but the pollen on 

 which I made 

 the experiment 

 was taken from 

 plants in the 

 month of Octo- 

 ber, and the ac- 

 tion did not begin till the pollen had been some time in 

 water, and it continued for nearly an hour in many of the 

 grains ; others ejected the whole of their particles in less 

 than a minute. The pollen of a hollyhock, which had been 

 between the plates of mica in the slider of a microscope 

 at least fifty years, emitted the particles very copiously, after 

 immersion in water for four or five minutes. They were of 

 different magnitudes, some being more than four times the 

 size of others. When these particles were detached from 

 each other, by stirring the drop of water, they continued to 

 move about for some time, like the Animalcula infusoria : but 

 when the grains of pollen had ceased to eject more particles, 

 and the agitation from external causes ceased, I could never 

 perceive any active motion of the particles, though I have 

 repeated my observations frequently with different micro- 

 scopes. 



The first remarkable circumstance which takes place when 

 the pollen is immersed in water is, sometimes, a change of 

 form in the grains of pollen themselves. I was greatly sur^. 

 prised to see the pollen of the sweet pea change almost in-' 



