REACTIONS OF NECTURUS TO STIMULI THROUGH SKIN 97 



gills were moved rapidly. -Reese ('06) in a similar experiment 

 found two of the five Necturus under experiment gave loco- 

 motor responses at 18° C. 



When put into water at 4° from 30°, the animals showed 

 the same responses as noted by Reese ('06) — that is, marked 

 activity, walking rapidly up and down the tank. 



The reactions of certain regions of the body of Necturus to 

 hot water was tested. A pipette that ejected 5 C.C. of water 

 at a time was used and tests were made in water at 10° C. 

 When the gills were stimulated with water at 70° C. the animal 

 walked forward thirty inches, switching the body from side to 

 side. The head, nostrils and tail were somewhat less sensitive. 

 Their stimulation with water at 70° C. resulted in a forward 

 movement of from eight to twelve inches. Water of the same 

 temperature ejected on the back, caused only two or three 

 inches of movement. The same regions of the body were tested 

 in a like manner with 30° C, with no response. 



Local heat stimulation was tested in another manner. A 

 long rubber tube was run through the tank of water containing 

 the animals. At one end of the tube was a funnel; the other 

 end was open and hung outside of the tank. This arrangement 

 allowed water to be poured in at the funnel, run through the 

 tube and empty outside of the tank. To secure local response 

 to heat, the tube was placed in contact with that region of 

 Necturus to be stimulated. The tank water during this test 

 was 0° C. and the water poured through the tube was 96° C. 

 The tube was placed in contact with the body and the water 

 was poured in at the funnel. When the nostrils, head and 

 gills were stimulated the animal drew away from the tube im- 

 mediately. This showed that direct response resulted from the 

 heat radiating from the tube containing the heated water. 

 Scarcely any response was induced from any other region of 

 the body. 



Another experiment was performed in which one end of a 

 large pan, three by one and one-half feet, containing water was 

 placed over a lighted gas burner and the other end on a cake 

 of ice. The temperature of the heated end was 40° C, the 

 cold end was 3° C, and the middle 10° C. Three animals were 

 placed in the pan. They walked up and down several times, 

 and finally rested in the cold end. When in the hot end they 



