^ On the Action of the Pollen of Plants^ 



Mr. Needham has not only minutely and accurately described 

 the action of the pollen, but has correctly delineated it in the 

 act of ejecting the particles contained within it. He also 

 mentions having seen the particles move when within the 

 pollen of the pumpion. He appears, indeed, to have de- 

 scribed most of the principal facts, respecting the action of 

 pollen, that have yet been satisfactorily ascertained. As similar 

 microscopic observations at present engage the attention of 

 many distinguished naturalists on the Continent, it is but justice 

 to our own countryman, Mr. Needham, to bring forward the 

 discoveries which he made near a century ago. An account 

 of his work cannot fail to be acceptable to many of your 

 readers. 



In order that those who are not at present acquainted with 

 vegetable physiology may have a clear notion of Mr. Need- 

 ham's discoveries, it may not be improper to state that the 

 farina, or pollen, of plants, is that fine powder which may be 

 observed within many flowers, and is particularly abundant 

 in the white lily, where it occurs in the form of an orange- 

 coloured meal. This powder is supposed to perform the 

 important function of impregnating the seed. When seen 

 through a microscope, as Miss Kent well describes, in p. 232. 

 of your useful Magazine, "every particle appeal^ a little bag, 

 containing a meal yet finer." 



Pollen is generally translucent, and the smaller particles 

 may be seen within, like the seeds of a white currant, but 

 much smaller in proportion. The grains of the pollen of the 

 geranium are oval, and do not exceed the 400th part of an 

 inch in diameter, as I ascertained by a micrometer scale ; the 

 particles or granules within it do not exceed the 10,000th part 

 of an inch. The pollen of some plants, as the mallow and 

 hollyhock, is surrounded by minute spines, and, when mag- 

 nified, the grains resemble the seeds of cleavers or goose 

 grass (Galium Sparine). Mr. Needham, as will be shortly 

 shown, was the first who discovered the internal particles in 

 the grains of pollen, and attributed to them the property of 

 impregnating the seeds of plants. 



The first sixty pages of Mr. Needham's work contains an 

 account of his discoveries of the structure of the animalcules 

 in the milt-vessels of the calmar, a species of cuttle-fish. His 

 object is to prove that these minute animalcules have an in- 

 ternal organisation, resembling a pump and sucker, and con- 

 tain within them " opaque globules, in a kind of serous liquor," 

 nearly similar to what he afterwards discovered in the pollen 

 of plants ; and he considers these internal particles to be in 

 both cases the real fecundising agents. . The succeeding twenty- 



