REACTIONS OF THE SPOTTED NEWT 207 



olfactory nerves. This would seem to indicate that the greater 

 sensitiveness of the head region over other parts of the body to 

 chemical stimulus, while it may be due merely to a greater sen- 

 sitiveness of the skin of that region, is probably due to the sen- 

 sitiveness of the nasal and oral mucous membranes, and not to 

 any olfactory sense proper. 



SUMMARY 



i. Diemyctylus uses both sight and an olfactory sense in 

 securing food, though the latter is apparently the more important. 



2. The normal animal will follow and sometimes seize small 

 bits of cotton or cloth of various colors, but will seldom swallow 

 them ; and when such objects are swallowed they are later 

 disgorged. When fatigued with these objects so that it will no 

 longer snap at them the animal will almost always seize and 

 swallow bits of raw meat or earthworm. 



3. There seems to be no difference in reaction between bits 

 of raw meat and earthworms. 



4. There is about the same response to filtered meat juice 

 (both raw and cooked) as to the filtered juice from crushed 

 earthworms. The response consists in snapping at and seizing the 

 end of the pipette from which the juice is coming ; also in snap- 

 ping and searching motions after withdrawal of the pipette. 



5. With the exception of the head all parts of the body seem 

 to be equally sensitive to chemical stimulation. The head is 

 much more sensitive than the rest of the body, even after the 

 olfactory nerves are cut. 



6. There is no definite reaction to a strong solution of sugar. 



7. To a saturated solution of quinine a fairly strong negative 

 reaction is obtained when the head is stimulated, but no reaction 

 is obtained from other regions. 



8. Negative reactions to a 1% sodium chloride solution are 

 obtained from some animals when used upon the head. No 

 reactions are obtained from stimulation of other regions with a 

 solution more dilute than 4%. 



9. 2% potassium hydroxide solutions cause quick and ex- 

 tremely violent reactions upon both head and body. The most 

 dilute solution that causes reaction when ejected against the 

 head is .0078125%. The reactions to this reagent are more 

 violent than to any other chemical tried of equal percentage. 



10. N egative reactions to acids are also very marked, and take 



