276 



J. S. NICHOLAS 



under pressure of 12 mm. of mercury applied to external nares, 

 the nozzle being held at a distance of 1 mm. from animal. No 

 muscular reaction and no respiratory reaction. Under a pressure 

 of 36 mm., nozzle was held for three minutes with no reaction on 

 part of animal except a raising of head. When air current was 

 directed toward different parts of body (region behind the head, 

 in front of the limb, trunk region, and the tail region) there was no 

 reaction. 



If the animals are partly submerged in water and the air cur- 

 rent is allowed to produce a series of bubbles, the animal is 



TABLE 4' 

 ReacHo7i.s to odor streams 



STIIIULUS 



Earthworm 



Turpentine, oil of 



Carbolic acid 



Oil of cloves 



Oil of wintergreen 



Bergamot 



Aniline 



Ammonia, concentrated 



Formol, 40 per cent 



Chloroform 



Distilled water 



REACTION 



No reaction 



No reaction 



No reaction 



Shakes head — draws away 



No reaction 



No reaction 



No reaction 



Withdraws violently 



No reaction 



Withdraws from current 



No reaction 



Negative 



Negative 



Negative 



Positive 



Negative 



Negative 



Negative 



Positive 



N-egative 



Positive 



Negative 



^ A trial is designated as negative when there is no reaction after three minutes' 

 exposure; positive, when there is motor activity resulting from the stimulus. 



mechanically stimulated and snaps at the bubbles. This stimu- 

 lation is quite strong in the region just anterior to the forelimb, 

 and is active, although less so, in the tail region. The trunk 

 region proper shows but little sensitivity. 



In testing odoriferous currents, a maximum exposure of three 

 minutes was allowed, after which the trial was declared to be 

 negative. The reaction was designated as positive if the animal 

 moved toward the air current or away from it. A discussion of 

 the results obtained and a comparison with those of Risser will 

 be found in the next section. 



