366 Dr. Barry on a Main Cause of Discordant Views 



am indebted to the kindness of Prof. Allen Thomson. It needs 

 no description, affording unquestionable evidence of division and 

 subdivision — changes which observers have overlooked, or at 

 least in their consequences disregarded. These changes, with 

 those seen in fig. 2, and with what I am about to state, furnish 

 the explanation he requires. 



There first exists a line of bodies comparable to germinal spots. 

 Each spot divides into halves, and then each half into four parts ; 

 so that each spot comes to consist of eight particles, which eight 

 particles lie in two strata — four in each. This is shown by fig. 5 

 (also from nature, and drawn by Prof. Allen Thomson), the par- 

 ticles in outline representing the upper, and the shaded particles 

 the lower stratum. Dislocation takes place, a change imme- 

 diately following the division into halves. Of dislocation an 

 example is afforded by fig. 2 ikl, which presents a side view. As 

 dislocation proceeds, there arises in the clear space an appearance 

 which we call a transverse line. Of this line no satisfactory ex- 

 planation has yet been given. My belief is that it results from 

 particles belonging to the stratum not in focus. This, I think, 

 is shown by b and c in the drawings from nature, fig. 4, where it 

 is no longer a mere line that is seen, but there have come into 

 view particles not differing from those of the stratum that is in 

 focus. In harmony with this opinion is the following remark 

 by Prof. Allen Thomson, written by him opposite the drawing 

 from nature, fig. 5, viz. "The transverse line in the clear space 

 is seen when the lower side is in focus ; and coincides exactly in 

 the specimen figured with the margin a of the square particles 

 when the upper side is in focus." — The line of particles b, fig. 4, 

 affords an instance of longitudinal separation, exhibiting one 

 half of such a line as that at c in the same figure. There can be 

 no doubt that in these lines we see the smallest elements dis- 

 cernible with our highest magnifying powers. — The line a in the 

 same figure (fig. 4) appears to represent a state corresponding 

 to that of the line b ; but with this important difference, that in 

 a the particles are flat. Such flattened particles I sketched in 

 Mullens Archiv for 1850*, and reproduce the sketch in fig. 3. 



In now proceeding to point out the ways, in one or more of 

 which I think it possible that such a line may pass into a spiral 

 form, I would ask a reference to drawings I gave from nature in 

 1842, after a long-continued examination of the elements of fibre 

 at the earliest periodf. For I presume that no one will say that 

 what was seen of the earliest formation of fibre may not be ap- 

 plied in endeavours to throw some light upon its mode of repro- 

 duction. 



* Taf. XVII. fig. 29. 



t Phil. Trans. 1842, plate 7, figs. 45 to 48. 



