30 V. G. DETHIER 



Zotterman, Y. 1949. The response of the frog's taste fibers to the application of pure 



water. Acta Physiol. Scand. IS: 181-189. 

 Zotterman, Y. 1950. The water taste of the frog. Exper. 6: 57-58. 



Chairman Gerard : We are very grateful to you for giving us this good sur- 

 vey of taste sense and smell sense and not too much nonsense. 



Dr. Wade H. Marshall (National Institutes of Health): I would like to 

 plead guilty to being a dunce; I missed the third neuron on that fly system. 



Dr. Dethier: You have nothing to plead guilty about because nobody knows 

 what this one does. We have been unable to trace its fiber beyond the base 

 of the hair. This would make it a very fine candidate for mechanical reception 

 as found in other receptors but, unfortunately, it does not conform to this 

 concept and this hair does not respond very well to mechanical stimulation. 



There are those of my colleagues who would be happy if this were some sort 

 of a ganglion cell. All I can say is heaven forbid. 



Dr. Roscoe Brady (National Institute of Mental Health): On the slide 

 with the increasing chain in fatty acids on the taste rejection, where you get 

 into the four, five and six carbon fatty acids, you immediately come into the 

 stench range and, of course, must rule out the smell with these taste studies. 



Dr. Dethier: The data which you saw were for insects and it is possible, 

 with these very handy beasts, to work either with taste or with smell without 

 the other interfering because one can remove all of the olfactory receptors and 

 render the animal completely anosmic. 



Dr. Manuel Morales (Naval Medical Research Institute): I have two 

 related questions. At two points in your talk you indicated the possibility of 

 some chemical reaction, and I believe you were thinking of the stimulant as 

 being a substrate in this reaction, something that is used up and perhaps, if 

 one washed it away one wouldn't get all of the stuff back. Of course, the sec- 

 ond possibility is that the stimulant could be acting as an activator or an in- 

 hibitor on the reaction that was using up something else. I wondered if you 

 would, perhaps, say if the other mechanism has been considered. 



The second question was: In those cases where you have two substances 

 that are very similar and yet different in their effect — I think you mentioned 

 the D and L formula, would it be possible in those cases, if you had a tracer, 

 to decide whether the substance is actually incorporated as a receptor and can- 

 not be washed away or whether it can be washed away? This, of course, bears 

 on deciding between the two possibilities in my first question. 



Dr. Dethier: In answer to your first question, we have considered both 

 possibilities that you mention. We have not carried this to the point where 

 we have experimentally any more evidence for one than for the other. I might 

 add that this is very recent work and you are hearing the early stages of it. 



