18 
ORGANOGRAPHY. 
BOOK I. 
ceil, to which they give an appearance like that of a little 
gallery with two rows of pilasters, the connecting arches of 
which remain after the destruction of the roof and walls. 
According to the observations of Dr. Schleiden, the formation 
of fibre never takes place independently of membrane, but 
occurs in the interior of cells, whose membrane was originally 
quite simple. He regards Corda’s statements to the contrary 
( Ueber Spiralfaserzellen^ 7. and 8.), as formed upon imperfect 
observations. He says that cells always attain their full size 
before the fibre appears, and he regards its formation as a part 
of the process of lignification. In the beginning he states 
that each cell is filled with starch, rarely with mucus or gum. 
By degrees the starch is always converted into the latter; 
this becomes changed, and, as it w^ould seem, always from 
without inwards, into jelly. This jelly changes at its surface 
into a spiral fibre of variable width, which either does or 
does not adhere to the sides of the cells, and which may be 
supposed to owe its spiral direction to the course taken by a 
current setting between the side of the cell and the central 
mass of jelly. 
The following are the more important varieties : — 
1. Spiral fibres repressed by mucus, but having sufficient 
elasticity to uncoil when the mucus is dissolved, and then 
breaking up into rings. (Plate I. fig. 16.) These are what 
are found in the seed-coat of Collomia linearis. They approach 
spiral vessels so very nearly, that when I originally discovered 
them I mistook them for such. They are known by their 
depressed figure when at rest, by the want of an inclosing 
membrane, and by their brittleness when uncoiled. 
2. Fibres short, straight, and radiating, so as to form little 
starlike appearances, found in the lining of the anthers of 
Poly gala Chamaebuxus, &c. by Purkinje. (Plate I. fig. 19.) 
3. Fibres originating in a circle, curving upwards into a 
sort of dome, and uniting at the summit, observed by the 
same anatomist in the anthers of Veronica perfoliata, &c. 
4. Fibres standing in rows, each distinct from its neigh- 
bour, and having its point hooked, so that the whole has some 
resemblance to the teeth of a currycomb, in the anthers of 
Campanula; first noticed by Purkinje. (Plate I. fig. 18.) 
