428 
The somewhat similar but much simpler coiling of the fibre obtained 
in the case of (9) was due apparently to an accidental cut, made 
while exposing the cord during fixation, at a point about two inches 
in front of the experimental incision. In this case all of the fibre lying 
behind this point where it was cut after death was withdrawn backwards, 
towards the point where the experimental incision was made, into a 
simple spirally twisted piece (Pl. I, Fig. 6) about half an inch in 
length, the central canal in front of this being empty. 
2. 
In the second group there has apparently been, in every case, a 
recoil of the fibre backwards from the point where the incision was 
made. This recoil must have been very violent, for in no one of these 
cases has the sinus terminalis been preserved intact, indeed, in most 
cases it has been entirely demolished and is represented merely by 
a mass of debris amongst which coiled pieces of the fibre may doubt- 
fully be identified. 
Retraction of the fibre forwards from the point of cutting has 
also occurred in every instance (with the possible exception of No. 4) 
but only in the one example (10) has evidence of a tangle remained 
(Pl. II, Fig. 10). In this instance, a loosely looped mass is found 
at the free end but the fibre here shows no trace of the usual spiral 
coiling. I am inclined to interpret this tangle as the result of an 
incomplete straightening out of a particularly extensive recoil. This 
specimen showed quite the most marked reaction and one which per- 
sisted for three full days, but I must admit, nevertheless, that the 
slowness of the process of uncoiling (if I am correct in so interpreting 
it) is rather surprising. 
Two others (5, 7) present little difficulty. The reaction was less 
pronounced (the recoil doubtless less extensive) and already the tangle 
had straightened out but had not pushed backwards the end of the 
shortened thread to the point where the cut was made. In the 
specimen (4) the free end was more or less firmly held by a blood clot. 
Specimen (F) had had the sinus terminalis destroyed and the fibre 
broken by some accident (vide ante) and although the fibre had 
become completely uncoiled regeneration had scarcely commenced. 
That a comparatively long period must have elapsed since the injury, 
without any considerable degree of regeneration having occurred, may 
perhaps have been due to the nature and severity of the injury, for 
the complete removal of the covering tissues in the region affected 
had left the end of the filum terminale wholly exposed. The damage 
to REISSNER’s fibre had also doubtless been considerable. 
