184 GEORGE E. NICHOLLS 
should expect that the reaction would continue until the fiber had 
reéstablished its attachment to the walls of the sinus terminalis 
and had once more attained to its normal tension. 
The reaction did persist, indeed, in some specimens until the 
attachment was practically made good (2) or until the termi- 
nation of the experiment (9). Occasionally the reaction was 
manifested intermittently for several days (5, 6) while in one 
case (24) it reappeared after several days of apparent normality. 
On the other hand, a reaction was sometimes marked during the 
early hours of an experiment but was not noticed subsequently 
(7) although the sections showed that the fiber had been broken 
but gave no indication that the new terminal attachment was 
completed. 
While, then, it is quite possible that in some specimens (in 
which the reaction had seemingly disappeared and which were 
killed very soon after the operation) the reaction might have 
reappeared at intervals had the experiment been prolonged, it 
is probable that in many the reaction would have apparently 
completely vanished (as in 7). 
Nevertheless, it seems unlikely that the effect produced by 
the breaking and retraction of the fiber can really altogether 
disappear until the tension of the fiber has been restored. 
The more obvious irregularities of the pose are possibly soon 
corrected, to a large extent, by the aid of the other senses, no- 
tably that of touch, and these corrections would be likely to 
become more exact as time passed, thus accounting, In some 
measure, for the gradual diminution in the magnitude of the 
reaction. It is, however, extremely probable that there may 
have been other reactions which persisted long after the speci- 
mens seemed to me to be normal. Especially may this have 
been the case with minute irregularities in action, in swimming, 
for whilst in motion the correcting influence of the sense of 
touch, at least, would almost certainly be eliminated. The 
motion of the animal is particularly difficult to observe closely 
and defied my attempts at analysis so that, although at times 
I felt convinced that the action was not exactly that which is 
