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JACQUES LE MAGNEN 



On the basis of this analogy it seems possible to suggest the hypothesis that 

 the overall mechanism of the discriminative process in olfaction acts in the 

 same way as that involved in the visual discrimination of" anamorphous " 

 figures. In " anamorphous " or superposed figures, two figures known by 

 the subject are mixed. The perceptual phenomena involved in the separa- 

 tion or discrimination of these mixed figures are well known, especially the 

 important role, in the discovery of the secondary figure masked in the pre- 

 dominant form, of the meaning of this figure and of the knowledge of this 

 masked figure by the subject. These perceptual phenomena are the exact 

 parallel of those revealed in the olfactory discrimination of more or less 

 diff'erent impulse-patterns induced at the peripheral level by two molecules, 

 and the isolation of different specific patterns inside the overall patterns 

 induced by a complex mixture of molecules, and are dependent on the same 

 central factors associated with the " meaning " of the stimuli. 



To illustrate this assumption T shall give a single example. Suppose that 

 the pattern induced at the peripheral level by the molecule of hexachlor- 

 exane may be pictured as in A (Fig. 1), by the differential activation of only 



B L 



Fig. 1 



ten independent units. Suppose also that the pattern induced by camphor 

 may be described as in B. If the specific pattern of isoborneol is that illu- 

 strated in C, consisting of the superposition of the patterns A and B, one 

 can explain why we smell the specific odour of isoborneol as a mixture of 

 musty and camphor odour (as with a mixture of hexacyclohexane and 

 camphor). One can also explain why we differentiate these two quahties 

 in the order of a molecular unit when we know, and only if we already 

 know, the separate odours of musty and of camphor. 



