246 CONTRIBUTIONS TO 



sumed, which, when the cell is moistened with water, comes 

 forth in form of an intestine (wie ein Darm hervortritt), and in 

 swelling expands itself over the fibres, thus appearing to sur- 

 round them ; this is the case in most Salvia and Polemoniacecs, 

 in Senecio flaccidus, Ocyinum polystachyum and polycladum 

 {Lumnitzera, Jacq.) There is an intermediate form between 

 this and the former, when the jelly itself forms a broad 

 spirally-wound band, which appear upon its surface to be com- 

 posed of innumerable delicate fibres ; their occurrence in this 

 state is very beautifully shown in Perdicium Taraocaci and 

 Zizipliora. A still less advanced stage of development exhibits 

 merely a cylinder or cone of gelatine in the interior of the 

 cell, the surface of which, however, is marked with delicate 

 spiral lines. This is seen in some Salvia, in S. verticillata for 

 example, and in Leptosiphon androsaceum. Finally, the lowest 

 stage of development is where the gelatinous cylinder, which 

 is furnished with spiral strise, has a cavity in its interior con- 

 taining starch, which has not as yet undergone decomposi- 

 tion : this instructive phenomenon is found in Dracocepjhalum 

 moldavica, Ocymum basilicum, and some allied species. In illus- 

 tration of the above, consult plate 2, figs. 1-10, with their 

 exjnanations. 



Before quitting the subject of spiral fibre, I will merely 

 add, what indeed has been of late admitted by every good 

 observer, that the only difference between spiral cell and spiral 

 vessel consists in the dimensions, although constant transitions 

 may be observed between them just as well as between the cells 

 of the liber and the parenchyma ; and consequently, as regards 

 this doctrine at least, there is no longer any place for natural- 

 philosophical phantasies about the arrestment of ideal forms of 

 higher types, and such like empty words. That which forms a 

 liber-cell out of a round cell, the preponderating expansion of an 

 organ lengthwise, is also that which transforms the spiral cells 

 (the vermiform bodies) into spiral vessels. The function of the 

 spiral fibre, however, is, as every candid vegetable physiologist 

 will certainly admit, entirely unknown to us at the present 

 time. It is certain that spiral vessels and spiral cells occur in 

 the living plant quite as frequently filled with sap (in the 

 younger vegetating portions) as with air (in the older organs 

 which have attained their full size) ; and it is this which has 



