184 The Philippine Journal of Science 1917 



of the cell was composed of a mass of pigmented granules; ra- 

 diating pseudopods filled with granules extended in all directions. 

 In the skin sections taken from lizards in which the melano- 

 phores were "contracted," it was observed that the peripheral 

 portion of the pseudopod was composed of farblose granules. 

 The melanophore of the lizard is, then, a definite fixed stellate 

 cell composed of granules which may be either pigmented or 

 colorless. "Farblose" and "colorless" are not used in their 

 literal meanings; we use them as terms indicating the appear- 

 ance of granules that have been depleted of their dark pigment. 

 These bleached granules have a slight yellowish tinge. 

 Hooker further states, 



It may safely be concluded that, in the normal ontogenetic origin of 

 melanin in the frog the chromatin plays no direct role. On the contrary, 

 all the evidence obtained goes to demonstrate that melanin granules are 

 formfed in the cytoplasm from elements already present in solution in 

 it, through some action of the nucleus. 



To arrive at some definite conclusions regarding these pig- 

 mented and farblose granules, a series of experiments was carried 

 out. It was believed that if a means could be found to destroy 

 the pigment, an actual observation could be made under the 

 microscopic. For these experiments small fragments Of skin, 

 4 millimeters square, were removed from the back of a lizard; 

 the pieces of skirl were then spread and floated on the surface 

 of an adrenalin solution. The strength of the solution used 

 was 1: 10,000 (1 part of adrenalin chloride to 10,000 parts of 

 Ringer's solution). As soon as the specimen was prepared, it 

 was placed under the microscope and it was observed that the 

 granules in the periphery of the pseudopod gradually began to 

 fade. This fading process progressed rapidly toward the center 

 of the cell. Some melanophores were completely depleted of 

 their pigment, others showed the central pigmented mass remain- 

 ing, and still others had scattered fragments or groups of pig- 

 mented granules separated entirely from the center. The stroma 

 of the pigmented cell remained in situ, clearly visible, and- 

 of a pale yellow color. These are also shown in the section of 

 cleared skin from the lizard bleached normally within white 

 surroundings (Plate I). 



In the above experiments, the skin was floated on the surface 

 of the solution. This was found necessary, since the results 

 were not as constant when fragments of skin were submerged. 

 Local application of adrenalin to the skin of a dark lizard in 

 dark surroundings results in the prompt fading of the area that 

 is moistened by the solution (Plate II, fig. 1). 



