841 



where only female specimens grow. No one has succeeded in making 

 out the mode in which the antheridia act upon the rudimentary fruit; 

 but the physiological fact just mentioned does not lose its force on 

 that account. 



" A second family indicating the necessity of an impregnation, were 

 the Rhizocarpeae, since numerous observations had shown that the 

 large and small spores of these plants could not be separated without 

 preventing the former growing into new plants. Schleiden, indeed, 

 had extended his theory of the development of the embryo from the 

 pollen-tube to this family, and arranged them with Phanerogaraia. 

 But nothing was gained by this, for, on the one hand, Schleiden's 

 whole theory of impregnation proved a false beacon ; on the other, 

 Schleiden's statements as to the Rhizocarpeae were not confirmed, 

 and this more particularly in the most essential point, the mode of 

 origin of the embryo. 



" Then unexpectedly appeared Count Leszcyc-Suminski's essay on 

 the development of Ferns, the contents of which at first seemed fabu-* 

 lous, so contradictory were they to all that was known of the organi- 

 zation and development of plants. But a more minute study of this 

 treatise — a compai-ison of the author's results with nature — soon 

 showed that although he had been deceived in a few particulars, his 

 account was far from being a creation of the fancy, and that his 

 researches had broken open a path to a long series of discoveries. 



" In all families of the leafy Cryptogamia (with the exception of the 

 Lycopodiacese) antheridia have been discovered, exhibiting, it is true, 

 considerable variations of external form and structure in the different 

 families, but collectively agreeing in the circumstance of developing 

 in their interior very delicately- walled cells, at first containing an 

 amorphous substance coloured yellow by iodine, in place of which, 

 at the epoch of maturation of the antheridia, a delicate filament pre- 

 sents itself, displaying several spiral convolutions, thickened at one 

 end and running off to a very fine point at the other. The filaments 

 manifest lively motions, exhibiting differences according to the man- 

 ner in which they are rolled up, in some cases while still enclosed in 

 the cells where they are developed, but more particularly after they 

 have emerged into the water from the antheridium, which opens when 

 ripe. Thus, when the filament is rolled up like a watch-spring, the 

 motion is more or less rotatoi'y, but if it is coiled over in the form of 

 a cork-screw, the movement is at the same time an advancing one. 

 In these movements the thin end of the fibre almost always goes first. 

 Minute observation, which in many cases is very diflScult, both from 

 VOL. IV, op 



