MARTIN BARRY ON FIBRE. 239 



Among vegetable structures, he subjected to microscopic examina- 

 tion the root, stem, leaf-stalk, and leaf, besides the several parts of the 

 flower ; and in no instance of phanerogamous plants, where a fibrous 

 tissue exists, did he fail to find filaments of the same kind. On subse- 

 quently examining portions indiscriminately taken from ferns, mosses, 

 fungi, lichens, and several of the marine algae, he met with an equally 

 general distribution of the same kind of filaments. The flat filaments 

 seen by the author in all these structures, of both animals and plants, 

 he states to be that usually denominated a. fibre. Its appearance is pre- 

 cisely such as that of the filament formed within the corpuscle of the 

 blood. It is known, he remarks, that discoid corpuscles circulate in 

 plants ; and it remains to be seen whether or not filaments are formed 

 also in these. 



By gradually tracing the fibre or filament above mentioned into 

 similar objects of larger size, the author endeavours to show that it is 

 not impossible to draw a line of separation between the minutest filament, 

 and an object being to all appearance composed of two spirals running 

 in opposite directions, and interlacing at certain regular intervals ; an 

 arrangement which produces in the entire object a flattened form, and 

 gives it a grooved appearance. It is, in fact, the structure which, for 

 want of a better term, he has called a flat filament. The edge of this 

 filament presents what, at first sight, seem like segments, but which, in 

 reality, are the consecutive curves of a spiral thread. A transverse 

 section of such an object is rudely represented by the figure 8. This is 

 also precisely the appearance presented by the minutest filament, gene- 

 rally termed fibre ; and the author particularly refers to the oblique di- 

 rection of the line separating the apparent segments in the smaller fila- 

 ment, in connection with the oblique direction of the spaces between 

 the curves of the spiral threads in the larger one. 



The spiral form, which has heretofore seemed wanting, or nearly so, 

 in animal tissues, is then shown to be as general in animals as in plants. 

 Nervous tissue, muscle, minute blood-vessels, and the crystaline lens, 

 afford instances in proof of this. And if the author's view of identity 

 in structure between the larger and the smaller filaments be correct, it 

 follows that spirals are much more general in plants themselves than 

 has been hitherto supposed ; spirals would thus appear, in fact, to be as 

 universal as a fibrous structure. 



The tendency to the spiral form manifests itself very early. Of this 

 the most important instance is afforded by the corpuscle of the blood, 

 as above described. The author has also obtained an interesting proof 

 of it in cartilage from the ear of a rabbit, where the nucleus, lying loose 



