Prof. Henfrey on the Phenomena of Impregnation in Plants. 439 



Notwithstanding a tolerably positive opinion, derived from a number 

 of eases in which the end of the pollen-tube and the germinal vesicle 

 were seen together, but distinct, in one preparation, the objects are 

 so delicate, and the causes producing obscurity so difficult to guard 

 against, that Mr. Henfrey cannot but think the demonstration of the 

 pre-existence of the germinal vesicle in the embryo-sac must be 

 considered the most important fact that can be brought forward in 

 opposition to the views of Schleiden. As remarked by Tulasne, it 

 has great philosophical importance in reference to the speculations 

 as to the source of the vitality of the new being ; and it is no less 

 important for the establishment of the relations of the processes of 

 embryogeny in the various classes of plants, and of the analogy which 

 these present to phsenomena attending the reproduction of animals. 

 The details of Mr. Henfrey's researches were given with great exact- 

 ness, and were illustrated by many excellent sketches. The memoir 

 was chiefly occupied in describing the course of development of the 

 ovule of one plant, in which the complete series of observations have 

 been repeated many times. Other fragmentary corroborative re- 

 searches being set aside, the facts detailed, though not now brought 

 forward for the first time, were offered as supplementary, partly con- 

 firmatory, partly emendatory, of the memoirs on the same subject by 

 the late Mr. Griffith. "The investigation itself," Mr, Henfrey re- 

 marked, "had derived a melancholy interest from the materials 

 having been furnished by the late lamented Dr. Stocks." 



After describing many of his microscopic examinations, Mr. Hen- 

 frey continues, " I have directed my utmost efforts to the accurate 

 observation of the ends of the embryo-sacs with the pollen-tubes 

 adherent. They are tolerably easily extracted with needles under a 

 low doublet. I have examined at least five-and- twenty, and have 



applied every means to make the structures clear The end of 



the pollen-tube adheres so firmly to the end of the embryo-sac, that it 

 cannot be torn away in a really fertilized ovule. My decided opinion 

 is that Griffith was in error in stating that the pollen penetrates into 

 the embryo-sac ; I believe that it only applies itself firmly against it, 

 over the point where the line of division exists between the two coagula 

 lying in the apex of the embryo-sac. But I incline to believe that 

 a phsenomenon analogous to conjugation takes place. Moreover, very 

 soon after the pollen-tube becomes adherent, the pre-existing proto- 

 plasmic globule acquires a proper coat of cell-membrane, becomes 

 a real cell, the germinal vesicle from which the suspensor is developed. 

 I think the contents of the pollen-tube, after it becomes adherent to 

 the summit of the embryo-sac, pass into the latter, reach the germ- 

 globule, and determine its conversion into a cell The facts 



relating to the germination of the Fucacese and Confervse described 

 by Thuret and Cohn, together with those brought forward in this 

 paper, tend to prove that the process of impregnation in plants con- 

 sists in the absolute admixture of the protoplasmic substance of two 

 cells ('male' and 'female'), of which the female (or germinal) 

 substance or body always pre-exists in the form of a nucleus, or ' pro- 

 toplast,' while the male (or spermatic) substance exists in the form 

 of a granulose fluid. In the flowering plants the spermatic fluid is 



