750 DR ALEXANDER BRUCE AND DR JAMES W. DAWSON ON 
33). A further stage in their evolution was reached by the convoluted course of the 
fibres, which seemed to coil spirally round other parallel longitudinal fibres or round 
a bundle of fibres cut transversely (fig. 38). 
From these simpler formations we get all transitions to the tuft-like nodules, in 
which the interlacing is so dense as to appear an almost inextricable tangle (fig. 30), 
or to the whorl-arrangement, in which the fibres appear to have some definite plan— 
the most typical being the ball-of-wool appearance already noted (fig. 29). Sometimes 
the appearance was that of a ball of wool in which several successive threads had 
passed in the same direction and then suddenly the winding had commenced in 
another direction, so as to cross the former in varying degrees of obliquity ; successive 
threads were then parallel for a time, till that direction again gave place to another. 
The increase in size of the nodule was accounted for by an agglomeration of bundles 
of fibres which simply repeated the primary groupings. At other times it seemed 
that each individual thread had wound in an independent direction, as if the ball had 
slowly revolved during the process of winding. On cross-section of such a ball, the 
fibres would then present an appearance much more uniformly transverse, while in 
the former case the fibres would be cut transversely, obliquely, and, even for short 
lengths, longitudinally (fig. 8). 
It is impossible to give anything like an accurate description of the almost infinite 
variety in the disposition of the fibres. The fibres in their windings could sometimes 
be followed for a considerable distance, and at other times they seemed to bend at 
very sharp angles, often at right angles. The ball-of-wool appearance, in some form 
or other, was characteristic of the larger nodules—whether they were looked at, as it 
were, from the surface or on section. 
(b) Structure and Mode of Formation of the Nodules. 
Structure.—Van Gieson sections—We have already indicated that by simple 
nuclear staining and superficial examination the nodules might have been mistaken 
for leio-myomatous new formations. Under a higher magnification, the fibres com- 
posing the nodules were found to have the structure of the peripheral nerves, 
differing from these only in the closer disposition of the neurilemma nuclei and the 
finer structure, in general, of the fibre. Longitudinally cut fibres were stained — 
yellowish-green, with a central thread—corresponding to the axis-cylinder—tuking 
sometimes the pink stain of the fuchsin or the dark stain of the hematoxylin, and 
with a very fine pink line which at frequent intervals showed an elongated nucleus 
in relation to it (fig. 6). Transversely cut fibres appear as discs with a central point— 
the axis-cylinder—and an outer zone staining homogeneously yellowish-green, and 
each with a pink ring which gives the dise a very sharp contour (fig. 6), and with an 
occasional nucleus applied to it. In nodules with fibres more closely arranged than 
in fig. 6, the cross-section of the fibres was angular and flattened from pressure, 
