Because, as odours and effluvia _ascend_, the nose is directed towards them, and thereby receives the readiest intimation of those bodies floating in the air which may be pleasurable to the sense, or offensive to the smell, and injurious to life. [Verse: "Can that which is unsavoury be eaten without salt? or is there any taste in the white of an egg?"--JOB VI.] 995. _Why is the nose placed over and near the mouth?_ Because, as one of the chief duties of that organ is to _exercise a watchfulness_ over the purity of the substances we eat and drink, it is placed in that position which enables it to discharge that duty with the greatest readiness. CHAPTER L. 996. _Why do we taste?_ Because the tongue is endowed with _gustatory_ nerves, having the function of _taste_ as their _special sense_, just as the _optic_, the _auditory_, and the _olfactory_ nerves, have their special duties in the eyes, ears, and nose. 997. _Why do some substances taste sweet, others sour, others salt, &c.?_ It is believed that the impressions of taste arise from the various _forms of the atoms of matter_ presented to the nerves of the tongue. 998. _Why do we taste substances most satisfactorily after they have remained a little while in the mouth?_ Because the nerves of taste are most abundantly distributed to the under surface of the tongue; and when solid substances have been in the mouth a little while, they impregnate the saliva of the mouth with their particles _and come in contact in a fluid solution with the gustatory nerves_. 999. _Why if we put a nub of sugar to the tip of the tongue has it no taste?_ Because the gustatory nerves are _not distributed to that part of the tongue_. [Verse: "Wine is a mocker, strong drink is raging; and whosoever is deceived thereby is not wise."--PROVERBS XX.] 1000. _Why, when we draw the tongue in, do we recognise the sweetness of the sugar?_ Because the dissolved particles of sugar are _brought in contact_ with the nerves of taste. 1001. _Through what nerves are we made sensible of the contact of sugar with the tip of the tongue?_ Through the nerves of _feeling_, which are abundantly distributed to the tongue to guide it in its controul over the mastication of food. 1002. _Why do connoisseurs of wines close their mouths and distend their chins for a few seconds, when tasting wines?_ Because they thereby bring the wine in contact with the under surface of the tongue, _in which the gustatory nerves chiefly reside_. 1003. _Why do they also pass the fumes of the wines through their nostrils?_ Because _flavour_, in its fullest sense, comprehends not only the _taste_, but the _odour_ of a substance; and, therefore, persons of experience attend to both requisites. The various conditions of taste are defined to be:-- 1. Where sensations of _touch_ are alone produced, as by glass, ice, pebbles, &c.