52 



DON TUCKER 



circuit is shown in the second trace. Positioning of the electrode tip is 

 critical for recording asynchronous activity from the mucosa. A very small 

 advance after the initial contact with the mucous surface is optimal, pro- 

 vided that the layer of mucus is thin. 



10 



10 



^u^s-*^L«^L*-L-.*Wv.V-.\ 



U 



u 



10 10 



2 MV 



I MIN 



XJv^h- 



REPLICATION 



V-"^-'Ni*'-^rr^^-rrA»"''^'7-*'^**-M.-^ii»X-iiUi ^i-n^r^V'^'-'^V*^*^''^'*'^*'*"n>J 



Fig. 7. Olfactory mucosal recording with Ag-AgCl-Cl" electrode. The first 

 trace is output from the d.c. amplifier recorded directly and the second trace 

 is output from the a.c. amplifier after passage through Beidler's integrator circuit. 



Many of our data are in the form of integrator records taken with a.c. 

 amplification because they are easily obtained and quantified. Stimulus 

 quantification is achieved with a dilution type olfactometer to vary con- 

 centration of odorant, a system to control nasal flow rate and a switching 

 mechanism to alternate between clean and odorous air independently of 

 nasal flow rate (Tucker, 1962). 



Olfactory- Vomeronasal Comparison 



It was a surprise to find the vomeronasal receptors in the tortoise res- 

 ponding to odorants as readily as do the olfactory receptors. There would 

 appear to be no doubt about identification, for the termination of the 

 vomeronasal nerves in the accessory olfactory bulbs is definitive, as may be 

 seen in Fig. 2. Besides, one can readily distinguish between the two kinds 

 of receptors after a little practice by testing with selected odorants. This 

 is conveniently done with the puff technique of stimulation, using wash 

 bottles containing small quantities of the odorants. The intensity of 

 stimulation is varied by controlling the strength of the squeeze and the 

 distance between the tip of the nozzle and the naris. 



The basis for comparison in simultaneous recording experiments is 



