cited above will leave no doubt as to its reliability, and the
accuracy of discrimination possible on these after-images.

[22] Lamansky, S., (Pflüger's) Archiv f. d. gesammte
Physiologie, 1869, II., S. 418.

[23] Guillery, (Pflüger's) Archiv f. d. ges. Physiologie, 1898,
LXXI., S. 607; and 1898, LXXIII., S. 87.

As to judgments on the color and color-phases of after-images, there
is ample precedent in the researches of von Helmholtz, Hering, Hess,
von Kries, Hamaker, and Munk. It is therefore justifiable to assume
the possibility of making accurately the four simple judgments of
shape and color described above, which are essential to the two proofs
of anæsthesia.


V. SUMMARY AND COROLLARIES OF THE EXPERIMENTS, AND A PARTIAL,
PHYSIOLOGICAL INTERPRETATION OF THE CENTRAL ANÆSTHESIA.


We have now to sum up the facts given by the experiments. The fact of
central anæsthesia during voluntary movement is supported by two
experimental proofs, aside from a number of random observations which
seem to require this anæsthesia for their explanation. The first proof
is that if an image of the shape of a dumb-bell is given to the retina
during an eye-movement, and in such a way that the handle of the
image, while positively above the threshold of perception, is yet of
brief enough duration to fade completely before the end of the
movement, it then happens that both ends of the dumb-bell are seen but