166 JOHN N. LOWE 



the tissues, to the threshold stimulus and as the process of 

 dilution continued the point was reached where the concentration 

 fell below the threshold and a relaxation (expansion) of the 

 melanophores occurred. After a complete recovery of the em- 

 bryos from the effects of the alcohol the pigment cells reacted 

 normally to other stimuli. 



These results show clearly that very weak solutions "of ethyl 

 alcohol do not have any effect on the pigment cells of the trout 

 embryos. This is in harmony with the work of Kobert ('82) 

 on the frog's muscle, Lee and Salant ('02) on the gastrocnemius 

 muscle of the frog, and Carlson ('06) for the heart muscle and 

 heart ganglion of Limulus, all of whom observed that weak or 

 very weak solutions of ethyl alcohol had no stimulatory action. 

 Ethyl alcohol in contractions of 1.3 per cent to 2.5 per cent water 

 shows a decided stimulatory action on the pigment cells of brook 

 trout embryos. This is in accord with results of others on the 

 primary stimulation of ethyl alcohol. Pickering ('95) has shown 

 that alcohol excites the embryonic heart muscle of the chick. 

 Scheffer ('00) has observed that in the frog's gastrocnemius when 

 it was treated with alcohol the capacity for work was increased. 

 If the muscle was curanized the stimulating effect of alcohol 

 was nil. O. Loeb ('05) has noted that in solutions of 0.13 to 

 0.3 per cent that the action of the isolated mammalian (cat) 

 heart was augmented. Wood and Hoyt ('05) have shown that 

 small amounts of ethyl alcohol increased the force of the heart 

 beat in the frog, snake, tortoise, and turtle. Lee and Salant 

 ('02) have demonstrated that in medium concentrations of ethyl 

 alcohol there was an increased rate of contraction and relaxa- 

 tion in frog's muscle (gastrocnemius), Carlson ('06) has ob- 

 served that for the heart muscle and heart ganglion of Limulus, 

 alcohol stimulated. Vernon ('10) has shown that alcohol has an 

 excitatory effect on the isolated heart of the turtle (Emys) . The 

 ('02) observed a marked increase in the number of contractions 

 of the bell of the Medusa Gonionema in ethyl alcohol of 0.5 

 to 0.25 per cent. 



In a strong concentration of 4.5 per cent there was a marked 

 depression or an expansion of the pigment cells. In this con- 



