178 GEORGE E. NICHOLLS 
in the ‘avoidance reaction,’ for Sargent’s calculations apparently 
suggest that, in an animal a metre in length, the passage of a 
stimulus along the conduction path alleged to be provided by 
Reissner’s fiber might effect a saving of one-fiftieth of a second, 
at most. 
I believe myself that there is nothing in this behavior but 
what may reasonably be attributed to excitement due to the 
handling inevitable to the change of accomodation, the strange- 
ness of the new environment and the frantic attempt to escape 
from the more cramped enclosure. It is interesting, therefore, 
to find that in one specimen, described by Sargent as probably 
abnormal, because it had been in confinement for a considerable 
period (and was therefore accustomed to its enclosure) this 
blundering into stationary and movable obstacles (the ‘slow 
optical response’) was not observed. 
As already remarked, this heedlessness in movement disap- 
peared in my specimens (control and experimental) within a 
few days when the fish had become accustomed, presumably, 
to its new surroundings. In the case of the subjects of Sar- 
gent’s experiments (in which the septic condition set up in the 
brain, by the operation, brought about a marked lethargy and 
speedy death) there was insufficient time for the specimens to 
become habituated to an alteration in their environment. 
While, therefore, certain of the phenomena observed by Sar- 
gent are, in my opinion, to be attributed merely to a change in 
the external condition of his specimens or to the ill-effects of the 
operation upon the entire organism, others of the reactions, upon 
which Sargent has laid little stress, may very well, I think, have 
been a consequence of the breaking of the fiber. Sargent noted 
that the fish adopted most abnormal attitudes in swimming, 
actually turning even and swimming (not floating) ventral sur- 
face uppermost. One specimen is described as swimming ‘with 
its head curved dorsally’ a reaction clearly suggesting a loss of 
control of the posture. In none of my experiments was there 
manifested so marked a reaction, but in none of my experiments | 
was the fiber cut so near to the subcommissural organ (in the 
fourth ventricle). 
