Closely associated with the sense of touch is the _temperature-sense_. Goldschneider and others have shown that on the skin of the human hand, for example, there are special points that are sensitive to heat and cold. Some of these little specialized areas are sensitive to cold; others are sensitive to heat; and neither of these seem to be sensitive to pressure. It therefore seems probable that special nerve-fibrils are set apart for the temperature-sense; but of the manner in which these fibrils terminate little or nothing is known. Let us note that this temperature-sense, unlike the sense of touch, may make us aware of distant bodies. It is, then, what we may term a _telæsthetic_ sense in contradistinction to a contact-sense. It is stimulated by a molecular throb; the throbbing body may be in contact, but it may be as distant as the sun, in which case the molecular pulsations are brought to us on waves of æther. Whether these waves act directly on the nerve end-organs, or indirectly on them through the warming of the skin-surface in which they terminate, we cannot say for certain. But if the hand be held before a heated stove and be sheltered from the heat by a screen, the removal of the screen, even for the fraction of a second, gives rise to a strong stimulation of the temperature-sense, though the skin-surface be not appreciably raised in temperature. Hence it is probable that the end-organs are stimulated directly, and not indirectly. Concerning the temperature-sense in the lower animals, nothing definite is known. But it is impossible to see our familiar pets basking in the sunshine, or a butterfly sunning itself on a bright summer's day, without feeling confident that the temperature-sense is a channel of keen enjoyment. As before mentioned, however, this is not to be regarded as the primary end in sensation. The primary end is not life-enjoyment, but life-preservation. And we must regard the temperature-sense as developed in the first instance to enable the organism to escape from the ill effects of deleterious heat or cold, and to seek those temperature-conditions which are most helpful to the continued and healthful fulfilment of the process of life. * * * * * The _sense of taste_ is called into play by certain soluble substances, or liquids, which must come in contact with the specialized nerve-endings. Under normal circumstances, the sense of taste is closely associated with that of smell, the result of the combination of the two special senses being a _flavour_. The _bouquet_ of a choice wine, the flavour of a peach, involve both senses; quinine involves taste alone; and garlic and vanilla are nearly, if not quite, tasteless,--what we call their taste is in reality their action on the organ of smell. It is difficult to classify tastes. Sweet, bitter, salt, alkaline, sour, acid, astringent, acrid,--these are the prominent and characteristic varieties.