96 MARY HONOR A SAYLE 



(d) Reactions to Clove Oil and Turpentine 



Drops of clove oil were ejected upon the skin of Necturus 

 with no results, except a slight response in the region of the 

 nostrils. When Necturus, however, raised its body out of the 

 water and thus carried some of the oil upon its skin, every 

 portion was sensitive. 



Cotton was saturated with turpentine and applied to Nec- 

 turus with no result, whether the animal was in or out of water. 



(e) Summary of the Chemical Reactions 



1. Necturus is more sensitive to nitric than to hydrochloric 

 or sulphuric acid. It is least sensitive to acetic. Responsive- 

 ness, is therefore, roughly proportional to degree of electrolitic 

 dissociation. 



2. Necturus is more sensitive to potassium sulphate than to 

 potassium chloride. 



3. Necturus is less sensitive to alcohol than to the acids, 

 alkalies, or alkaline earth salts, as indicated by the high per 

 cent of alcohol necessary to induce reactions. 



4. The skin of Necturus is sensitive to clove oil in the air 

 but not when under water. Whether in or out of the water, 

 Necturus does not react to turpentine. 



THE REACTIONS TO HEAT 



Several experiments were performed with three individuals 

 to determine the thermic reactions of Necturus. 



When taken from the tank where the water was 10° C. and 

 put into water at 30° C. the three animals made the most vio- 

 lent struggles, beginning almost immediately and lasting until 

 they were completely exhausted. The violence of these strug- 

 gles was quite remarkable, though less pronounced in some 

 cases than in others. A very short stay in the warm water 

 was sufficient to completely exhaust all the individuals, so that 

 they turned ventral side up; but when returned to water of 

 moderate temperature they soon recovered. 



Removal from water at 10° C. to 25° C. induced locomotion 

 also. The gills were spread out and moved rapidly. The nos- 

 trils were often lifted above the water and air was expelled. 



At 18° C. and 15° C. the animals remained quiet, but the 



