53 
Table XV , — Mydriatic action of adrenalin upon the frog^s eye when exposed to bright 
sunlight. 
Experiment 17, July 22, 1908. Rana pipiens. Weight about 17 grams. Killed 10.13 a. m., enucleated 
10.18. The solutions made from P., D. and Co.’s 1: 1,000 adrealin solution. The temperature varied from 
29.8° to 32.5° C., and the hrightnessof the light varied from the bright noonday sunlight to that which obtains 
at 4.30 p. m. of a clear July day. ( — ) always indicates decrease in size, i. e., constriction of the pupil. 
Ringer. 
A. 
Adrenalin solution 
+ Ringer 
1:5,000,000 
B. 
Adrenalin solution 
+ Ringer 
1:2,500,000 
c- 
Adrenalin solution 
+ Ringer 
1:625,000 
D. 
Ringer. 
E. 
Long 
Short 
Time. 
Long 
Short 
Time. 
Long 
Short 
Time. 
Long 
Short 
Time. 
Long 
Short 
C. 
axis. 
axis. 
axis. 
axis. 
axis. 
axis. 
axis. 
axis. 
axis. 
axis. 
A.m. 
M.m. 
M.m. 
-1. m. 
M. m. 
M.m. 
A . m. 
M. m. 
M. m. 
A. m. 
M.m. 
M. m. 
A. m. 
M. m. 
M. m. 
10.20 
1.4 
2.6 
10. 22 
1. 5 
2.5 
10. 24 
1.5 
2.5 
10. 02 
1.5 
2.8 
10. 30 
1. 5 
2.6 
'29.8 
10. 33 
In adr. 
10. 33 
In adr. 
10. 33 
In adr. 
10. 33 
al. 1 
2.4 
10. 30 
1. 1 
2.4 
10. 40 
1.3 
2.4 
10. 45 
1.4 
2.6 
10. 47 
1.5 
2.8 
30.0 
b-.S 
— . 2- 
- .4 
- .1 
_ . 2 
- .1 
- .1 
— . 2 
.0 
+ .2 
10. 50 
1.1 
2.4 
10.52 
1.4 
2.4 
10. 54 
1.3 
2.0 
10. 50 
1.1 
2.5 
11 
1.1 
2.5 
30.5 
- .3 
- .2 
- .1 
- .1 
- .2 
- .5 
- .4 
- .3 
- .4 
- .1 
11.00 
1.2 
2.3 
11. 02 
1.2 
2.2 
11. 04 
1.2 
2.0 
11 
1.0 
2.4 
11. 20 
1.0 
2. 1 
31.3 
— . 2 
- .3 
- .3 
- .3 
- .3 
— . 5 
- .5 
- .4 
— . 5 
— . 5 
11.40 
1.1 
2.1 
11.42 
1.1 
2.1 
11. 44 
1. 5 
2.1 
11. 04 
1.1 
2.4 
11. 50 
1.1 
2.4 
32.5 
- .3 
— . 5 
- .4 
- .4 
.0 
- .4 
- .4 
- .4 
- .4 
- .2 
P. m. 
P. m. 
P. m. 
P. m. 
P. m. 
12. 20 
1.2 
2.2 
12. 32 
1.2 
2.3 
12.24 
1. 5 
2.3 
12. 28 
1.2 
2.4 
12. 30 
1.2 
2.4 
31.8 
- .2 
- .4 
- .3 
- .2 
.0 
_ . 2 
- .3 
- .4 
- .3 
- .4 
12.53 
1.3 
2.3 
12. 55 
1.4 
2.4 
12. 56 
2.0 
2.5 
12.59 
1.1 
2.4 
1.1 
1.1 
2.4 
31.0 
— .1 
- .3 
- .1 
- .1 
+ . 5 
.0 
- .4 
- .4 
- .4 
— .2 
2.04 
. 1.4 
2.7 
2. 06 
1. 5 
2.3 
2. 08 
2.4 
2.6 
2. 12 
1.4 
2.5 
2.14 
1.5 
2.6 
31.0 
.0 
+ .1 
.0 
- .2 
+ .9 
+ .1 
- .1 
- .3 
.0 
.0 
3. 14 
1.6 
2.6 
3. 16 
1.5 
2.8 
3. 18 
2.6 
2.8 
3. 22 
1.6 
2.5 
3. 24 
1.7 
2. 5 
31.5 
+ .2 
.0 
.0 
+ .3 
+1.1 
+ .3 
+ .1 
- .3 
+ .2 
- .1 
4.14 
1.9 
2.6 
4. 16 
1.6 
2.5 
4. 18 
2.7 
2.9 
4. 22 
1.6 
2.6 
4.24 
1.9 
2.6 
30.6 
+ .5 
.0 
+ .1 
.0 
+1.2 
+ .4 
+ .1 
— . 2 
+ .4 
.0 
o First line in each group indicates actual length of axes in millimeters. 
^ Second line in each group shows change in length of axes. 
Other investigators in their experiments with adrenalin and the 
excised bulbus used sunlight, which as is well known varies greatly 
in intensity. Since the stimulating action of adrenalin is supposed 
to counteract the stimulating action of light it would seem of the 
greatest importance to use light stimuli of a constant value and of 
optimum intensity. This, I believe, I have accomplished by the use 
of electric light which, so far as I know, has never been used before 
in experiments of this nature. 
In the first place the constricting effect of very bright sunlight is 
usually greater than can be overcome by the dilating effects of the 
