6 
B. Experimental— Qontimiedi. 
2. Toxicity experiments with, white mice — Continued. Page. 
h. Synthetic dl-adrenalin hydrochloride 39 
Subcutaneous injections 0.002 to 0.020 mg. per gram body weight. 
Lethal dose. 
Relative toxicity of natural 1-adrenalin and of synthetic 
dl-adrenalin. 
c. Arterenol hydrochloride 40 
Subcutaneous injections varying from 0.004 to 0.080 mg. per 
gram body weight. Lethal dose. 
Relative toxicity of arterenol and natural 1-adrenalin. 
d. Homorenon hydrochloride 44 
Subcutaneous injections 0.237 to 1.137 mg. per gram body 
weight. Lethal dose. 
Relative toxicity of homorenon and natural 1-adrenalin. 
3. Measurement of mydriasis in the frog’s excised bulbus 48 
Criticism of earlier methods. Objections to naked-eye observa- 
tions. F actors that influence the reaction of the iris of an excised 
eye. Objections to the use of ordinary sunlight for lighting the 
eyes under observation. Effect of mechanical stimuli. Points 
of reference upon the margin of the pupil useful in locating the 
axes of a dilated eye. Use of an instrument of precision in 
measuring the eye. Control of light and temperature. 
a. Natural l-adrenalin base 55 
Effect of 1 : 2,000, 1 : 5,000, 1 : 25,000, 1 : 625,000, and 1 : 
3,125,000 solutions. 
Advantage of using the right and left eye of the same frog instead 
of choosing eyes promiscuously. 
h. Synthetic dl-adrenalin hydrochloride 59 
Mydriatic effect of solutions in a concentration of 1 : 2,000, 
1 : 5,000, 1 : 25,000, 1 ; 625,000, and 1 : 3,125,000. 
Comparison of eyes treated with natural l-adrenalin and s\Tithetic 
dl-adrenalin. 
Relative actPuty of natural and s\mthetic adrenalin. 
4. Theoretical 68 
Dakin’s Auew of the importance of the catechol nucleus and of 
the side chain. 
MTiat the present experiments suggest. 
5. Summary and conclusions 70 
6. Bibliography 71 
