915 



was practicable, by means of careful dissection, to bring into distinct 

 view the apex of the ovule, bearing a tube projecting from the atte- 

 nuated extremity or neck of the nucleus, and also to ascertain that the 

 tube was continuous with the inflated portion of the neck of the nu- 

 cleus, lying immediately above the point where the rudimentary em- 

 bryo first makes its appearance. This tube is in every respect similar 

 to the pollen-tube itself, and I have traced it from the stigma to within 

 a very small distance of the ovule, along the channels of stigmatic tis- 

 sue which extend to the back of the placenta, which organ, in all 

 probability, constitutes the termination and broadest expansion of 

 the stigmatic tissue. It is certain that a mass of loose tissue, in every 

 respect the same as that proceeding downwards from the stigma, is 

 always found in close apposition with the apex of the ovule, so that 

 the entrance of the pollen-tube may be effected without any specific 

 action of the ovule ; but inasmuch as the pollen-tube (if such it be in 

 reality) is frequently swelled out and crooked immediately above its 

 point of insertion into the nucleus, and the apex of the primine, at 

 the period of fecundation, is fringed and gaping (though it is after- 

 wards nearly closed upon the nucleus), it is possible that some action 

 analogous to that of the Fallopian tubes may be excited at the proper 

 juncture. In two instances two pollen-tubes seemed to have reached 

 the ovule, one of them not being inserted into the nucleus, but inter- 

 posed between the primine and the nucleus. It will still admit of a 

 doubt whether the tube at the extremity of the nucleus be not a pro- 

 longation of the nucleus itself, to meet the pollen-tube at some point 

 to which the fertilizing influence is conveyed ; for in one particular 

 instance the upper end of the tube proceeding from the nucleus was 

 closed up, and rounded at its extremity, the interior being so full of 

 grumous matter as to bear being cut in two without sensible derange- 

 ment, and the extremity of the tube was so firmly connected with a* 

 number of cellules of stigmatic tissue as to forbid the supposition of 

 any continuity of that tube with any proper pollen-tube above it. 

 With this solitary exception my observations are in accordance with 

 the opinion that the pollen-tube does actually extend to the ovule. 

 Previous to fecundation, the long, slender neck of the nucleus is cer- 

 tainly quite destitute of any tubular centre : a transverse section 

 shows an uniform mass of cellular tissue, containing active molecules, 

 and the apex is compact and entire ; but immediately after fecunda- 

 tion it is so loosened as to exhibit a fringed, expanding orifice, with 

 the membranous tube passing down to the bottom of the neck of the 

 nucleus, where it expands to nearly twice the diameter. Usually the 



