54 
adrenalin present in a 1 : 5^000,000 or even in a 1 : 62o;000 solution. 
Therefore; the readings from the start have a negative sign, that is, 
the pupil constricts. It is only after remaining in the solution two 
or three hours that signs of dilation appear, and even then there is 
no positive evidence in favor of the adrenahn causing this dilation. 
The readings in cohmms A and E of Table XV are from eyes in 
Kmger solution. The maximum constriction is — .3 for the long axis 
and — .5 mm. for the short axis of A; — .5 by — .5 mm. for E. Later, 
as the light grows dimmer and the temperature lower, the same eyes 
dilate making the chfference in their sizes a little after 4 p.m. from 
that when first measured for A -f.o by .0 mm.; and for E +.4 by 
.0 mm., the pupils at the end being slightly larger than when first 
measured. It is true that C shows greater dilation than this, even 
as much as +1.2 by +.4, but D in a much stronger solution of 
adrenalin than C dilates less. In the light of simliar sets of experi- 
ments, I am inclined not to stress the importance of adrenalin in 
bringing about the dilation in B, C, or D, for if they had been in 
Kinger solution alone they would without doubt have reacted in 
much the same way. On the whole I found sunhght unsatisfactory. 
TTith few exceptions, eyes under its infiuence in weak solution con- 
stricted, and if there were dilation later, it was only after exposure 
to Ringer solution and at a temperature which my previous experi- 
ence with salt solutions has shown to be positively injurious to all 
muscle tissue. 
Mechanical stimuli are likewise an important factor in bringing 
about dilation of the pupil. Due care must be taken in changing the 
solution and in orienting the pupil, especially at such temperatures 
as render smooth muscle unusually irritable. 
Table XVI. — The effect of mechanical stimuli upon the pupil of the excised bulhus, 
J:ept at a constant temperature and lighted by artificial light. 
Time. 
Long 
axis. 
Short : 
axis, i 
Time. 
Long 
axis. 
Short j 
axis. 1 
Time. 
Long 
axis. 
j Short : 
1 axis. ' 
1 , 
A. m. 
M. m. 
JT. m. ; 
A. m. 
Jf. m. 
M. m. 
A. 772 . 
Jff. 777 . 
if. 772 . 
10. 12 
2.235 
2.055 1 
11. 51 
1. 975 
0. 945 
1. 12 
1. 670 
1. 170 
10. 25 
2. 220 
1.860 1 
11.58 
1. 670 
1. 165 
1. 15 
1. 710 
1.200 
10.48 
1.835 
1.440 1 
P. m. 
1. 20 
1.825 
1.400 ! 
11. 18 
1.535 
0.970 j 
12. 2 
1.735 
1.290 
1.26 
1. 950 
1.645 I 
11.29 
1. 515 
0.960 1 
12. 11 
1.695 
1.240 
1.36 
1.935 
1.610 ; 
1 11.46 
1.490 
0.900 * 
12. 37 
1.635 
1. 045 
1.48 
1.850 
1. 405 
' 11. 48 
By means of a | 
12. 48 
1.650 
1.150 ; 
2.8 1 
! 1. 815 
1. 310 
capillary pipette the eye is j 
1.2 
1.635 
l.OSO 
2. 27 
1. 800 ; 
1. 370 
gently pipetted about in its j 
1.9 
' Ringer pipetted 
bath and then oriented as 
off and : 
2 c. c. of a 1:3,125,- j 
usual. 
000 solution of adrenalin | 
added. 
