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THE EFFECT OF ADRENIN ON THE PIGMENT MIGRATION IN THE 
MELANOPHORES OF THE SKIN AND IN THE PIGMENT CELLS 
OF THE RETINA OF THE FROG. 
ANDREW J. BiagNry, Evansville College. 
(Author’s Abstract) 
(The original printed in “The Journal of Experimental Zoology” Vol. 27, 
No. 3, January, 1919.) 
The frogs used were mostly Rana pipiens Schreber. The adrenin em- 
ployed was that prepared by Parke, Davis & Co., and sold under the name 
of Adrenalin Chloride, in strength 1 to 1,000. 
In the melanophores of the skin, the pigment in the light expands, while 
in the dark it contracts. On injecting adrenin in frogs which had been 
in the light for six hours, it was found that the melanophores were strongly 
contracted. The effect being opposite to that of light. The adrenin 
1:1000 and 1 :10000 strength gave the best results. 
The migration of the retinal pigment is outward in the light and into the 
cell in the dark. On injecting .06 ce of adrenin, 1:1000 into frogs kept six 
hours in the light, the pigment was found to be fully expanded after 7-15 
minutes exposure. Then other frogs were kept in the dark six hours and 
injected with same amount of adrenin and the pigment was also expanded. 
Control frogs in the dark showed the pigment contracted. So the conclu- 
sion was reached that the adrenin has the same effect as light. The retinal 
pigment was sensitive in solutions from 1:1000 to 1:1000000 and remained 
for three to four hours. 
The effect on the dermal melanophores is just the opposite to that on the 
retinal pigment. This is new to science. 
In the above experiments, the frogs were decapitated, eyes removed, 
hardened in Perenye’s fluid, imbedded, sectioned, and mounted unstained. 
