1852.] Linnean Society. 205 



filament contained in or hanging from the mouth of the canal of 

 the archegonium. I have seen the spermatozoids swimming in num- 

 bers around the mouths of archegonia, but never detected one inside, 

 and I do not see any good reason for supposing such a process 

 necessary. The pollen -tube of flowering plants only comes in con- 

 tact with the outside of the embryo-sac, and the influence is some- 

 times communicated through a long suspensor ; and there does not 

 seem to be any suflicient objection to the supposition, that the 

 contact of the spermatozoid with the filament of mucilage which lies 

 in the canal of the archegonium, suffices to convey the necessary sti- 

 mulus. I imagine this stimulus resides in the mucilaginous fluid in 

 which the spermatozoid is bathed in the sperm-cell, and which, ad- 

 hering to this, is conveyed to the mucilage (protoplasm) of the ger- 

 minal vesicle, just as the contents of the pollen-grain become com- 

 bined with the protoplasm of the germinal vesicle in flowering 

 plants. The nature of the process is clearly a problem beyond the 

 reach of science, but it seems to me a necessary induction from the 

 facts in the Phanerogamia, that the phsenomena result there from the 

 material union of two fluids, and I hence conclude that this is the 

 case here. The comparatively few cases of successful impregnation 

 among these prothallia, so many of which prove sterile, may perhaps 

 be accounted for by the peculiar conjunction of circumstances re- 

 quired to bring a sufficient amount of the fertilizing fluid, by means 

 of the spermatozoids, to the germinal vesicle, at the precise epoch 

 required." 



His general " conclusions " are as follows : — " In summing up 

 all these statements it becomes evident that the balance of evi- 

 dence is in favour of the existence of sexual organs, and of a process 

 of impregnation, giving rise to a new individual, as asserted by 

 Suminski, although under conditions somewhat different from those 

 described by that author. Only two of the observers who have re- 

 peated his investigations throw doubt upon these points, namely 

 Wigand and Schacht ; the statements of the former as to matters of 

 fact are far from sufficient to bear out the mass of argument he has 

 built upon them against the existence of sexes ; in fact, his obser- 

 vations were so imperfect that he described the two parts of the 

 archegonium, the papilla and the enlarged embryo-sac, as distinct 

 structures ; while he never traced the origin of the new plant at all. 

 His observations may therefore be safely passed over. Schacht's 

 are more complete, but he again only argues against the probability 

 of a sexual conjunction, with the preconceived notion that this must 

 be analogous to what he erroneously believes to be the conditions in 



