368 Dr. Barry on a Main Cause of Discordant Views 



bodies of the same form as mammiferous blood-discs, fig. 7£ a. 

 Each has its pellucid centre or nucleolus, which, when the outer 

 part assumes the spiral form, is left behind — a line of such 

 nucleoli being the foundation of future offspring. 



Now I have no doubt that a, fig. 4, passes into a twin spiral 

 in one of the ways just described. If in the first way, it pro- 

 bably undergoes longitudinal separation into two single piles 

 such as that in fig. 3 ; and then each pile forms a single spiral, 

 which by longitudinal division becomes a double one. But if a, 

 fig. 4, assumes the spiral form in either of the two other ways, 

 it undergoes no longitudinal separation, and it forms but one 

 twin spiral. 



It is obvious that the bodies df, fig. 2, pass into the bodies bd 

 in the same figure. The question is : what is the condition of 

 bd? Prof. Allen Thomson believes it to be double. I am of 

 the same opinion. Even he admits it to present "very much 

 the appearance of a spiral." And here also agreeing with him, 

 I would direct attention to a change in the direction of the 

 transverse line in the clear spaces, which direction in bd crosses 

 that of the transverse line in df It may therefore be that df, 

 fig. 2, consists of two strata of particles, which particles come to 

 alternate with, or overlap one another, as at B in fig. 6; and 

 that further changes, such as those just described, produce an 

 approach towards the completion of a twin spiral in fig 2 bd. 



Whether, however, an approach towards the completion of a 

 twin spiral is or is not exhibited in the fibril seen by Prof. Allen 

 Thomson and myself, and delineated by him in fig. 2 bd, I cer- 

 tainly saw a twin spiral at the upper end of the fibril in fig. 1. 

 This figure I published in the Edinburgh New Philosophical 

 Journal for October 1843, plate 5. fig. 2*. And as it exhibits 

 three states, viz. that of quadrilateral particles (c), division and 

 dislocation of these (b), and then as a continuation of the latter 

 the twin spiral (a) in the same fibril, I have thought the figure 

 deserving of reproduction here (fig. 1). Along with this figure 

 I published the following remarks, viz. " Were filaments formed 

 by each half-nucleus (fig. 1 b) of two adjacent rows to assume 

 the spiral form and interlace, and the filaments of the same row 

 to then unite, we should have the double spiral. [The oblique posi- 

 tion of the two rows of half- nuclei in fig. 1 b is not undeserving 

 of notice here.] f" 



It is satisfactory to find, that while the renewed inquiries made 

 known in this communication enable me to explain some details, 



* It represents a young fibril of muscle from the ventricle of a frog's 

 heart ; drawn as magnified 600 diameters. 

 t Edinb. New Phil. Journal, Oct. 1843, p. 214. 



