ODOR SPECIFICITIES OF THE FROG'S OLFACTORY RECEPTORS 27 



Fig. 6. A unit that responds strongly to camphor, two puffs of Hmonene, 

 carbon disulfide, and slightly to ethyl butyrate. Sweep lengths, 10 sec. Note 

 early response to carbon disulfide because of odor on the outside of the syringe 

 as it was brought into position. A lower amplitude spike also responds to 

 camphor in the top trace. 



Fig. 7. More responses from the same recording position as Fig. 6. Top trace 

 shows a weak, response of the two units to musk xylene. Below it, the one unit 

 shows long-delayed responses to nitrobenzene and benzaldehyde. The two 

 bottom traces show a larger unit, which was not responsive to the preceding 

 stimuli, slightly responsive to /?-butanol, and more so to pyridine. Sweep lengths, 



10 sec. 



