6. The regio olfactoria, or the olfactory membrane, has been said to give rise to taste sensations, and the question has aroused much dispute. The evidence for thus attributing taste to the smell mechanism consists in the discovery in the regio olfactoria of bodies similar to taste bodies, and the further fact that breathing chloroform through the nose gives rise to a stinging sensation, followed by a sweet taste. Introspection seems to localize this taste in the nostrils. Nagel, however, denied the existence of this so-called “nasal taste” and performed a simple experiment to prove his contention. He finds that if one allows chloroform or ether vapor to be blown into his nostrils he will get a burning sensation, followed in the first case by a sweet taste and in the second by a bitter taste. But if while the vapor is entering the nostrils the person constantly utters a vowel sound, thus closing the passage between the nasal and mouth cavity, the sweet and bitter tastes will disappear, while the burning sensation remains. Nagel holds that this shows that the taste sensations must be due to the stimulation of parts other than the nasal cavity. The same conclusion has been reached by the more careful researches of Nagel’s students and others upon individuals whose nasal cavity and mouth cavity have been effectually separated either by growths or by artificial means. One conclusion seems generally supported by the investigations of the distribution of taste, namely, that one cannot assert positively that wherever tastes have been definitely aroused there taste organs will be discoverable, or the converse of this, that wherever taste buds are found there taste sensations can always be aroused. ------------------------------------------------------------------------ CHAPTER VI SENSORY ELEMENTS OF THE TASTE MECHANISM _Taste Buds and Their General Characteristics_ EACH sense mechanism has an arrangement more or less mechanical for modifying the stimulus, and another mechanism which transforms the stimulus into the nerve impulse, that message which is carried from sense organ to brain and there gives rise to consciousness. We know very little about the real nature of this nerve impulse transmitted from sense organ to brain, aside from its speed and a number of conditions affecting it. Some call it a chemical phenomenon, others an electrical phenomenon, and still others an electrochemical or physicochemical one. We know even less—in fact, nothing—about the change from nerve impulse to consciousness. But there are certain facts fairly well determined by microscopical examination of the sense organ about the nature of the mechanism which transforms the physical stimulus into a physiological one. In the preceding chapter the more mechanical features of the taste mechanism have been reviewed, and in this one we will describe the transforming mechanism.