108 
DR. MARTIN BARRY ON FIBRE. 
and in a line. It appears to be by the union of the adjacent extremities of coils, that 
there is produced the spiral (see the same figure). Corresponding rings and coils in 
plants, I have not seen nor sought for : but, with so perfect an analogy before me as 
that above described, I do not find it easy to believe that they can be deficient there. 
Now were such rings not to form coils, nor even to divide, but simply to enlarge, a 
line of them, equidistant within a tube, would have very much the same appearance 
as the “ annular duct ” of plants. 
83. If the appearances delineated in figs. 87, 88, 89, 90, as noticed in the roots of 
a plant, be compared with those in fig. 25, from mould ; in fig. 91, from the cornea 
of the eye ; and in fig. 131, from the crystalline lens ; as well as with figures of vo- 
luntary muscle in the lower line Plate VIII., and in other Plates, I think it will not 
be easy to refrain from believing the appearances in all to be produced by the same 
kind of structure. This structure, in such of the figures now mentioned as were pre- 
viously referred to, we have seen to possess a spiral form. As already stated with 
reference to muscle (par. 42), spiral is formed within spiral ; and the outer spirals 
more or less completely coalesce to form a membrane. The vegetable figure, fig. 90, 
seems to represent an advanced state of such as that in fig. 87- In both, as well as 
in fig. 88, spirals were observed within a tube. These spirals appeared to interlace 
with one another ; and, by their close contact (fig. 90), to produce the appearance 
of transverse and elliptical “pores” or “dots.” The apparent “dots” or “pores” 
I believe were no other than spaces between the winds of spirals, contained within a 
tube. Now spirals interlacing in the above way (figs. 87, 88, 90) must, by a longi- 
tudinal succession of their winds, produce septa (fig. 90 a) in the containing tube. 
I cannot help believing that these observations will assist to solve the still undecided 
question, as to the structure of the “ dotted duct.” In short, I find it difficult to refer 
the appearance of the “dotted duct” to any cause but that above described, as pro- 
ducing the striae in voluntary muscle (par. 53|). 
84. The filaments in plants have often appeared to me to be so placed, that, by 
alternate contraction and relaxation, they might influence the contents of cells. And 
surely the structure of these filaments is sufficient to induce the belief, that they per- 
form an important office in the circulation, including the elevation of the sap. An 
office of this kind may perhaps belong to spirals in the roots, and elsewhere, such as 
those in figs. 87 to 90 ; exhibiting, as some of these do, almost transverse striee, like 
those of voluntary muscle in animals. 
85. A structure presenting the same appearance as that of the essential part of 
muscle, being found to pervade, it may be said, all other tissues, it is evident that 
this structure alone does not account for the contractile property of muscle. To 
what then is the contractile property of muscle owing? This inquiry my observations 
do not enable me to answer. It is the duty of an investigator to record the facts he 
