164 JOHN N. LOWE 



true also of other tissues, I refrain from applying the results to 

 such an interpretation. The literature is used in a compara- 

 tive way, but not in the sense that the results obtained with 

 melanophores are directly comparable. 



Ten per cent stock solutions of methyl (Sp. G. O. 796), ethyl 

 (Sp. G. O. 796-800) propyl (Sp. G. 0. 8066) alcohols of Merck's 

 manufacture were made up with oxygenated distilled water. The 

 dilutions were made from these stock solutions with oxygenated 

 distilled water. The experiments were carried on in glass stop- 

 pered bottles of 75 cc. capacity. All work was done at room 

 temperature of 18° to 20°C. 



1. Methyl alcohol. Overton ('01) showed that methyl alco- 

 hol has a less powerful narcotic action on tadpoles than ethyl 

 alcohol. Vernon ('11) confirmed that the same was true in the 

 depressing action of methyl alcohol on the • heart muscle of a 

 turtle's heart. 



Young brook trout embryos of the same age and condition were 

 subjected to the action of the respective alcohols of the various 

 concentrations. The contraction of the pigment cells was taken 

 as the criterion of stimulation, the relaxation (expansion) as 

 that of a depression. 



Ethyl alcohol in solutions of 1.6 to 2.5 per cent produced a 

 complete contraction of the pigment cells. Methyl alcohol of an 

 equal concentration did not cause a contraction. In a 3.5 per 

 cent solution there was a slight retraction of the pigment cells, 

 but the contraction was not complete. A 4.5 per cent solution 

 produced a complete contraction of the melanophores. Solu- 

 tions of 5 per cent to 5.5 per cent produced a slight contraction 

 of pigment cells. This partial contraction was followed by an 

 immediate expansion. If embryos in which the melanophores 

 were just contracted in a 0.005 per cent strychnine solution were 

 subjected to 5 per cent to 5.5 per cent methyl alcohol the pig- 

 ment cells expanded. In 7 per cent to 10 per cent solutions of 

 methyl alcohol there was no visible change in the expanded 

 melanophores. 



Thus it may be concluded that (1) methyl alcohol in high con- 

 centration acts as a depressing agent, (2) in medium concentra- 



