PINEAL GLAND FUNCTION 221 



1. Pineal emulsion on anesthetized tadpoles. Several tadpoles of 

 equal depth of pigmentation were completely anesthetized with of 

 ether after which half were placed in an emulsion of acetone 

 extract of beef pineal, the others in a like emulsion of muscle 

 tissue. Five minutes later those in the pineal emulsion were 

 preceptibly lighter, later acquiring a marked translucency. 

 The latter remained unchanged. The tadpoles recovered from 

 the anesthetic and gradually regained their original appearance. 



2. Hypodermatic injection of pineal emulsion. Several tadpoles 

 of equal depth of pigmentation were divided into two groups. 

 One received 0.01 cc. of an emulsion (1-500) of acetone extract 

 of pineal gland, injected hypodermatically into the peritoneal 

 cavity; the other received the same amount of normal saline 

 solution injected in a similar way. Shortly after injection the 

 pineal treated animals became lighter, eventually reacting to 

 the maximum degree of translucency. The other tadpoles 

 remained practically unchanged in appearance. As a further 

 control a third group was immersed in the pineal emulsion for 

 the length of time consumed in making the injection and the 

 tadpoles were then washed in tap water. They remained un- 

 changed. This control showed that the effect produced was 

 due to the injected pineal material and not to any accidental 

 absorption through the skin. 



3. Effect of pineal ejmdsiori on eviscerated tadpoles. A number of 

 tadpoles were completely eviscerated. These tadpoles live and 

 swim about as freely as their fellows. Following this procedure 

 part of the animals were removed to an emulsion of the acetone 

 extractive of beef pineal gland and shortly passed through the 

 same pigment changes as normal tadpoles placed in this emul- 

 sion at the same time. The eviscerated and normal tadpoles 

 remaining in tap water did not change in color. 



These observations prove conclusively that the principle 

 involved is directly absorbable through the gills or skin. The 

 effect is produced without the intervention of the processes of 

 digestion. There is no indication, however, as to whether the 

 principle acts directly upon the melanophores, or indirectly 

 through the medium of the central nervous system. 



