BITTERS, AROMATICS^ AND SIALAGOGUES. 399 



The control which we thus possess over food is the foundation 

 of the vast subject of dietetics. 



2. The sensory apparatus in the mouth can be variously 

 influenced. The variety of natural tastes and flavours 

 of which we may avail ourselves is endless ; artificial products 

 are hardly less numerous. The art of cookery is much 

 concerned with the proper use of these ; so is the growth of 

 wines; and the many natural and artificial condiments act 

 chiefly upon the palate, such as mustard, pickles, and sauces. 

 Beyond the culinary art, an immense number of medicinal 

 agents are contained in the materia medica which may be used 

 in therapeutics proper, to act upon the tongue and palate, and 

 thus upon the nervous centres and viscera. These may be 

 arranged as follows : (1) The great group of warm aromatic 

 oils, including Cloves, Allspice, Peppermint, Rosemary, Lavender, 

 Nutmeg, and many others, each with its own peculiar flavour ; 

 (2) bitters, such as Calumba, Quassia, Quinia, etc. ; (3) aro- 

 matic bitters, of which Gentian, Orange, and Cascarilla are 

 examples ; (4) the spirituous group, including Spirits, Wines, 

 Chloroform, and Ether ; (5) pungent substances proper, such as 

 Mustard, Horseradish, and Pyrethrum ; (6) sweet substances, 

 including Sugar, Liquorice, Glycerine, etc. ; and (7) acid 

 or sour substances, such as the Mineral Acids, Acid Fruits, 

 and Acid Tartrate of Potash, to which we shall presently 

 return. 



The value of aromatics, bitters, and the other stimulants 

 of the nerves of the mouth, lies in the fact that whilst they 

 increase relish or the enjoyment of eating, and thus the 

 appetite and the amount of food consumed, they provide 

 for the digestion of this increased quantity of nourishment 

 by stimulating the secretion of the digestive fluids in the 

 mouth, and, as we shall see in the next section, in the stomach 

 also. 



The effect of these substances on the palate also affords us 

 means of covering the tastes of nauseous medicines, of which we 

 constantly avail ourselves. On the other hand, we may 

 employ the unpleasant taste or flavour of certain drugs, such as 

 Valerian and Assafoetida, to produce through the afferent 

 nerves a powerful influence on the sensorium which we may 

 sometimes have occasion to employ. 



3. Salivary and mucous glands. Substances and measures 

 which increase the flow of saliva are called sialagogues (o-iaAoj/, 

 saliva, and frytiv, to cause to flow), and include the greater 

 number of the stimulants of the sensory apparatus just 

 classified. Of these the most important sialagogues are un- 

 questionably diluted acids, including the Diluted Mineral Acids, 



