470 — Researches into the Anatomy of Plants. 
2. Vessels with a fixed spiral. These vessels in the ap- 
"pearance resemble the above, but they cannot be unfolded: 
In the grasses and roots they are frequent. 
3. False trachee. The transverse lines, which traverse 
the vessels are very much interrupted. Frequently these 
transverse lines are a little undulated: the false trachea, 
P|. Ti. fig. 4. is taken from the Cucurbita Pepo. 
4. Porous tubes. The tube is studded with small dark 
points, as we see in fig. 5. Pl. II. in a vessel taken from 
the cucurbita pepo. Tn the sassafras wood we find porous 
tubes, the dark points of which completely resemble the 
pores, fig. 7. 
5. Vessels with false partitions.. All the above vessels 
are sometimes marked with obscure lines which seem to be 
partitions. Pl. Ti. fig. 5. exhibits these vessels taken from 
the stalk of abalsamine. These are not real partitions, for 
I have seen tincture of fernambouc fill the whole of the 
vessel. This is rather a derangement of the vessels as we 
see in fig. 5. letter a. 
6. Vessels like a string of beads. The false trachez or 
porous tubes sometimes exhibit narrow parts, which almost 
separate them at various parts. Pl. II. fig. 8. exhibits this 
kind of vessel taken from the root of the Symphytum offi- 
cinale. 
7. Vessels with false cellules. The false partitions some- 
times increase to such a degree, that the vessels resemble a 
cellular texture, studded with pores. [ have seen these 
vessels very often in the old stalks of the balsamine, and I 
have exhibited a piece in fig. 9. 
8. Annular vessels. These consist of several rings sepa- 
rated from each other. ‘These vessels are frequently at the 
same time vessels with fixed spirals, and the rings appear 
to be merely the residue of the turns of the spiral lamina. 
Fig. 10. is a vessel of this kind taken from the Feltheimia 
Quineensis. 
All these vessels certainly belong to the same class of 
organs, and they probably perform the same functions. 
We may prove this theory several ways. Ist. These vessels 
are nearly of the same size in a plant; if the spiral vessels 
are large, so are the false trachee, and vice versa. 2d. If 
the spiral vessels are wanting, all the rest of this class are 
also wanting, as is the case with the mosses, the naiades, 
the alge, &ce. On the contrary, the ferns which are pro- 
vided with spiral vessels have also false trachee, porous 
tubes, &c. 3d, We see vessels which are at one extremity 
spiral 
