CHAPTEK III 



THE SENSE OF TASTE 



CONTENTS. 1. Taste-buds the peripheral organs of the sense of taste. 2. Taste 

 area mapped out by the physiological method of adequate stimuli. 3. Qualities of 

 taste. 4. Mechanics of taste. 5. Correlation between the chemical and physical 

 constitution of sapid substances and the intensity and quality of the excited 

 tastes. 6. Inadequate stimuli; the so-called electrical taste. 7. Pathological 

 alterations of taste-sense by disease or poisons. 8. Specific energies of the nerves 

 of taste. Bibliography. 



IN close relation with the sensations that can be aroused from 

 the cutaneous surface is another series of specific sensations that 

 originate in the ectodermal mucous surfaces of the mouth and 

 nose. The Mouth is the seat of gustatory, the Nose of olfactory 

 sensations. The sense of Taste enables us to recognise certain 

 chemical qualities of the solid or liquid substances taken into the 

 mouth as foods ; that of Smell, certain chemical qualities of the 

 gaseous substances that pass through the nasal passages along 

 with the air inhaled. 



Taste and smell are two specific and closely allied senses 

 which may be termed chemical senses, not because their excitation 

 is due to any definite chemical alteration in the corresponding 

 sense-organs, but because the adequate stimuli for both these 

 senses consist in special chemical substances that are soluble in 

 water. 



Taste and smell often function together, to such an extent 

 that certain sensations which we locate in the mouth and call 

 " taste " are proved by physiological analysis to be due to the 

 activity of the sense of smell. 



From the teleological point of view both gustatory and 

 olfactory sensations are specially co-ordinated for the control and 

 selection of foods and beverages, while their seat at the cephalic 

 end of the digestive and respiratory systems enables them to act 

 together and to arouse complex sensations, made up not merely 

 of the elementary sensations of taste and smell, but also of the 

 sensations excited in the tactile, thermal, and algesic organs with 

 which the oral and nasal mucous membranes are richly provided. 



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