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 striae, 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 



