845. When these symptoms exist, the individual, in the first instance, should be placed in pure air, and friction and dry warmth should be applied to the pallid and cold skin. This should be assiduously persevered in until heat and color are restored to the skin and limbs, and due action of the heart and arteries has been established. Mild stimulants may also be used internally, with much advantage. The sympathizing friends should not be permitted to stand about the patient, as they vitiate the air. There should be no bleeding until the skin and extremities become warm. Send for a surgeon without delay. -=-=-=-=-=-=-=-=-=-=-=-= Give an instance where moderate concussion of the brain is produced. 844. What are the symptoms when the brain is injured from blows and falls? 845. What treatment should be adopted? -=-=-=-=-=-=-=-=-=-=-=-= CHAPTER XLI. THE SENSE OF TOUCH. 846. SENSATION is the perception of external objects by means of the senses. There are five senses, namely, _Touch_, _Taste_, _Smell_, _Hearing_, and _Vision_. 847. TOUCH is the sense by which the mind becomes acquainted with some of the properties of bodies, and enables us determine whether their surfaces are smooth or rough, their relative temperature, and, to a certain degree, their form and weight. 848. Some physiologists make a distinction between the sense of touch and tact. Tact, or feeling, is more general, extending over the whole surface of the skin and mucous membranes, while touch exists chiefly in the fingers of man and in the noses of certain quadrupeds. 849. "In the exercise of these functions, tact is considered passive; as, when any part of the system comes into contact with another body, a sensation of its presence is given, without the exercise of volition. On the contrary, touch is active, and is exercised voluntarily, for the purpose of conveying to the mind a knowledge of the qualities or properties of the surfaces of bodies; as when we feel of a piece of cloth to ascertain its qualities, or a polished surface, to prove its smoothness." 850. In man, the hand is admirably adapted to the exercise of touch. "The fineness of the skin, its great sensibility, the species of cushion formed by the sub-cutaneous fat at the extremities of the fingers, the length and flexibility of these organs, and the capability of opposing the thumb to the fingers, like a pair of forceps, are so many conditions essentially favorable to the delicacy of this sense, and enable us to appreciate with exactitude the qualities of the bodies we may feel." -=-=-=-=-=-=-=-=-=-=-=-= 846. Define sensation. How many senses have we? 847-851. _What is said of the sense of touch?_ 847. Define touch. 848. What is the difference between touch and tact? 849. In the exercise of these functions, which is active, and which passive? 850. Why is the hand so admirably adapted to the exercise of the sense of touch? -=-=-=-=-=-=-=-=-=-=-=-=