RESPONSES TO ODORANTS 



51 



into the naris from a polyethylene wash bottle containing the odorant. 

 Superimposed on the " slow potential " recorded with the d.c. amphfier 

 is the " asynchronous activity " recorded with the a.c. amplifier. It seems 

 natural to conclude that the d.c. record represents summation of action 



i»i v^» »^i^- ^ — »i^\>« 



FLA. ORANGE 





GERANIOL 





BUTANOL 





GERANIOL 



•v>*«-^A^^^MM*'«w^^HWWf^^ 



^ . J»A^ t, ^» »[^< Wtf!\) B^,>ife)B^ 



V 



•/^ 



0.1 SEC TIME MARKS 



0.5 MV 



Fig, 6. Records obtained (a.c. and d.c.) simultaneously from an olfactory twig 



about 30/< in diameter. Both amplifiers were driven from one cathode follower 



connected to the recording electrodes. 



potentials at the recording electrodes. A twig so small as 10// in diameter 

 could contain an upper limit of 2500 fibers uniformly 0.2// in diameter 

 (Gasser, 1956). 



Recording of slow potentials from the olfactory mucosa is a technique 

 that has become popular and for such records Ottoson (1956) has proposed 

 the name electro-olfactogram. It is also possible to record asynchronous 

 activity from the olfactory mucosa. However, the nerve is the best site 

 for recording asynchronous activity and the mucosa appears to be the 

 best site for recording slow potentials. An electrode similar in design to 

 Ottoson's, except that polyethylene instead of glass tubing was used, was 

 inserted through a small hole in the top of the nose and the residual open- 

 ing closed with silicone high-vacuum grease. Air was flowed through the 

 nose at constant rate and amyl acetate of various concentrations intro- 

 duced. The d.c. record is shown in the first trace of Fig. 7 and the asynch- 

 ronous activity after passage through Beidlefs (1953) " integrator " 



