XII, B, 4 Ruth and Gibson: House Lizards 185 



Lieben was perhaps the first investigator to record the action 

 of adrenalin on the melanophore and states : 



Gelegentlich einer Adrenalininjektion bei einem Frosche zum Zwecke 

 der Studiums ihrer Wirkung auf die Gefasse fiel mir auf dass sich die 

 Pigmentzellen sehr bald nach Beginn des Versuches ballten und der ganze 

 Frosch hell wurde. 



The adrenalin that we used was diluted in Ringer's solution, 

 1 : 10,000, and 0.1 cubic centimeter was injected into the 

 dorsal lymph sac of a normal dark lizard. Two minutes later 

 there was a distinct blanching of the localized area overlying 

 the injected sac, following which there was a gradual systemic 

 fading of the color of the lizard, so that in from ten to fifteen 

 minutes following the injection the entire skin was a creamy 

 white (Plate II, fig. 2) . Throughout the experiment the lizard 

 was kept in dark surroundings. Control animals injected with 

 Ringer's solution and placed in the same chamber showed only 

 a slight fading of the skin immediately surrounding the point 

 of injection. In numerous similar experiments the lizards al- 

 ways reacted promptly when newly prepared adrenalin solutions 

 were employed. 



We have tried in many ways to study other conditions that 

 might effect changes in the melanophore. Many of them have 

 been repetitions of those recorded by other investigators. Ex- 

 periments with ether and chloroform vapor, in vivo and in vitro, 

 were not conclusive- Carbon monoxide experiments resulted 

 similarly, though dark lizards placed in illuminating gas were 

 slightly bleached because of irritation attending efforts to escape. 

 Adrenalin placed on the skin or injected into the lymp sac was 

 still effective in anaesthetized and carbon monoxide lizards. Skin 

 placed in calcium saline or in potassium saline solution did not 

 change. Experiments with curare, atropine, and potassium 

 cyanide were negative. Application of the tetanizing current 

 to isolated pieces of skin was without effect. Exposure of the 

 lizards to temperatures between 0° and 30° C. produced no 

 change. Dark, dorsal skin, ground with sand and strained 

 through cloth, was not affected by adrenalin. Isolated pieces of 

 skin, killed by exposure to chloroform vapor, did not react to 

 adrenalin. 



Some interesting observations were obtained by the adminis- 

 tration of chloretone. When light-colored lizards in white sur- 

 roundings were injected in the dorsal lymph sac with 0.1 cubic 

 centimeter of 1 per cent chloretone solution, the skin overlying 

 the injected area soon became more and more pigmented (Plate 

 II, fig. 4) . Subsequently the entire lizard gradually became 



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