274 the president's address. 



all these instances must be accepted as remarkable analogies to 

 sensibility as exhibited in the animal world ; and, in a smaller 

 degree, the same may be said of the movements of the stamens in 

 some flowering plants, the irritability of the labellum in orchids,* 

 and even to those movements under the influence of light which 

 are known as " heliotropism," " dia-heliotropism," and " nycti- 

 tropism." " Why a touch," writes Mr. Darwin, " slight pressure, 

 or any other irritant, such as electricity, heat, or the absorption of 

 animal matter, should modify the turgescence of the affected cells 

 in such a manner as to cause movement we do not know. But a 

 touch acts in this manner so often, and on such widely different 

 plants, that the tendency seems to be a very general one, and, if 

 beneficial, it might be increased to any extent. "f 



Neither can we find in plants any such high development of what 

 is termed instinct as manifested in birds, dogs, horses, and other 

 animals, but there would seem to be faint indications of similar 

 tendencies even amongst plants, otherwise how is it that in such 

 Algas as (Edogonium certain privileged cells produce spermato 

 zoids, which, though limited in number, find out the small opening- 

 in the distant female cell, and straightway enter it and perform 

 the act of fecundation ? or in such other species as produce in cells 

 of a distinct and different filament, or plant, the active fertilizing 

 agents ? Or, again, in those species which produce active infu- 

 soria-like bodies from certain cells at some distance from the female 

 cells, and yet these bodies find their way not only to the cell, but, 

 according to the species, attach themselves either to the outside of 

 the female cell or to the cell which supports it, then elongate, and 

 develop into pigmy male plants, in time producing their own sper- 

 matozoids, which enter and fertilize the ovum contained in the 

 female cell, near or upon which they are located. Why do they 

 select a particular place, a particular cell, to which to attach them- 

 selves, so that when the spermatozoids are developed they are close 

 to the orifice, which it is essential for them to enter if the oospore 

 is to be fertilized ? This is only one instance, but others could be 

 alluded to if time permitted.^ 



* Darwin, " Fertilization of Orchids," p. 172. 



f " Movements of Plants," p. 571. 



\ Not to mention the problematical case of the spores of the Berberry 

 fungus travelling twenty miles, or even across the sea, in order to produce 

 mildew in wheat, which some mycologists seriously believe, or fancy that 

 they believe, although without analogy in the animal world. 



