THE FUNCTION OF REISSNER’S FIBER rw! 
great number of those delicate component fibrillae (as I believe 
them to be) which serve to support and stay the fiber along the 
length of the spinal cord. 
In the subject of two of the experiments (3, 49) the fiber had 
broken very far forward; of these, one failed to recover conscious- 
ness and gave no reaction, but it is extremely significant that in 
the other (49) the reaction took on a somewhat peculiar form. 
It is suggested, therefore, that in this case (where the breaking 
of the fiber must certainly have reacted upon the subcommis- 
sural organ), the more pronounced reaction was the sequel of 
an unusually extensive disorganization of the apparatus. 
In this connection, it is interesting to recall what has been 
recorded by Sargent concerning his experiments. That author 
laid much stress upon the fact that the subjects of his experi- 
ments would blunder, headlong, into obstacles (stationary or 
other). This behavior, as I have already pointed out (712, p. 
420), is to be noted in the lesser dogfish both in normal (con- 
trol) specimens as well as in the subjects of the experiments 
when removed from the comparatively spacious tanks of the 
aquarium to the smaller tanks in which, alone, one can be cer- 
tain of keeping them under close observation. Moreover, this 
blundering gait disappeared, after a few days confinement in the 
more limited space, in the subjects of the experiments as well 
as in the control specimens. 
_ In the larger sharks of which Sargent made use, and which 
were apparently freshly caught specimens, one cannot wonder 
at such a result. Moreover, Sargent had no opportunity to ob- 
serve the passing of this phase, for his specimens after a day or so 
became quite lethargic and died upon the fourth or fifth day of 
the experiment. Nor does the failure of the fish to avoid col- 
lision with the walls of its cage bear out Sargent’s contention 
that there was in these specimens, a delay in the transmission 
of the optical stimulus, for such an object, always present, 
would be visible for a sufficiently long period to allow any opti- 
‘eal stimulus to pass by the ordinary conduction paths. Even 
where an obstacle might be interposed with extreme sudden- 
ness it would have been scarcely possible to observe any delay 
