RESPONSES TO ODORANTS 65 



Stenson 0.3 ml of solution was introduced, which was sufficient quantity to 

 cause its appearance at the naris, and then the pharyngeal occlusion man- 

 euver was performed. Hamlin's (1929) suggestion of emptying and 

 fining of Jacobson's organ may be appropriate to this case. 



A curious finding was that with replenishment of mineral oil over the 

 cranial exposure a temporary increase in vomeronasal activity ensued. 

 Variation of temperature of the added oil showed that local cooHng was 

 the cause. The oil over the brain obviously equilibrates at some tempera- 

 ture above that of the room. The effect was obtained with active olfactory 

 and trigeminal twigs, from which it was seen that cooling at the recording 

 electrodes causes greater duration of impulses (Fig. 19), and consequently, 



*^t>^^\^\r'^»f*^* 



^f^ik/Z^M-^ffrffl l^ t:f^;/;Tr^r^/^;!f;^^^^ 







Fig. 19. Oscilloscope traces of sensory activity in ethmoidal nerve twig taken 



before and during stimulation with heptyl alcohol ; at temperature equilibrium 



of the oil bath for the first pair and after addition near the electrodes of 2-3 drops 



of oil at 10-12°C for the second pair. Time marks at 10 and 100 msec. 



a greater output from the integrator. The apparent greater sensitivity of 

 the vomeronasal nerve to local cooling probably means that background 

 activity of these receptors is high, at least for the conditions of the experi- 

 ments. Perhaps the vomeronasal receptors are performing in their function 

 without our recognizing the fact. 



Trigeminal Receptors 



Oscilloscope tracings of trigeminal receptor activity before and during 

 presentation of heptyl alcohol are shown in Fig. 19, which demonstrates 

 also the effect of cooling at the recording electrodes. In general, there is 

 some background activity, tending to synchronize with inspiration, for 



