206 MM. Garreau and Brauwers on Cell-formation, Growth, 



These cells, which are united so as to form an axis or cylinder, 

 whose free extremity ends in a hemisphere, have the form of 

 quadrangular prisms enlarged about the middle ; they decrease 

 from the base of the organ towards its apex, so as to become 

 cubical or tubular in that region, where, by the aid of a sufficient 

 number of preparations, it may be ascertained that those cells 

 which bound the hemispherical portion of the axis, devoid of 

 feculent granules, are furnished with proteinous substances col- 

 lected in each cell into two or four distinct masses, such as are 

 observed in the later phases of the development of pollen-cells. 



Very soon each of these masses, which continues the sym- 

 metry of a row of cells, becomes a new cell, so that the multi- 

 plication takes place by a binary or quaternary formation in the 

 interior of mother cells, and not, as Link supposed, at the ex- 

 pense of an extra-cellular cambium. We have not been able to 

 determine whether these new cells result from the formation of 

 simple septa in the mother cell, or by double septa produced by 

 the application together of the lateral walls of two young cells 

 formed around the masses of proteinous substance ; however, 

 we incline to believe that they originate in this latter manner, 

 because the most superficial layers of these cells are those which, 

 when pushed forwards, constitute the cortical zone, and, as we 

 have said, they exfoliate as complete isolated cells, which could 

 not be the case if there were only a simple septum formed in 

 the middle. 



The cells observed immediately above those which are in 

 course of multiplication, at first square and full of feculent 

 granules of extreme minuteness, become a little elongated in 

 the direction of the axis ; and while this elongation takes place, 

 the feculent granules disappear, and the living proteinous 

 matter, then visible, becomes condensed in each cell into two or 

 three irregular heaps, between which septa soon appear. These 

 new cells, whose smaller diameter is then parallel with the axis, 

 in part enlarge without undergoing change, and in part mul- 

 tiply by binary divisions pai'allel to the axis, becoming wider 

 and larger like the former, forming with them linear series 

 resembling those which are formed by the grains of maize on the 

 axis of the spike. One fact worthy of note is, that in propor- 

 tion as the cells of the radical axis multiply, we perceive, between 

 the parallel rows they form, dark lines (intercellular passages) 

 produced by the presence of air or some other gas which pene- 

 trates to within a short distance of the apex of the axis. This 

 mode of multiplication may be observed in the extremity of 

 the axis of millet, where it is even more easily traced than in 

 that of wheat. It is found also in the radicles of buckwheat, 

 barley, hollyhock, and the Leguminosce : everything leads to the 



