. Elements of biology; a practical text-book correlating botany, zoology, and human physiology. Biology. THE SENSES 4JJ flavored foods is found to dull the sense of t;iste. and ],v al(.<,],.,l .,t least, the olfactories are rendered less ; — Macv", /V///.svWoV//. The Organ of organ of hearing is the ear. In a irog, or reptile, the outer ear, so prominent in man, is entirely lacking ^ outer ear consists of a funnel-like organ composed largely „f cartilage whirli IS of use in collecting sound waves. This part of the ear the audi- tory canal which
. Elements of biology; a practical text-book correlating botany, zoology, and human physiology. Biology. THE SENSES 4JJ flavored foods is found to dull the sense of t;iste. and ],v al(.<,],.,l .,t least, the olfactories are rendered less ; — Macv", /V///.svWoV//. The Organ of organ of hearing is the ear. In a irog, or reptile, the outer ear, so prominent in man, is entirely lacking ^ outer ear consists of a funnel-like organ composed largely „f cartilage whirli IS of use in collecting sound waves. This part of the ear the audi- tory canal which is closed at the inner end by a tightly stretched membrane the tympanic membrane. We have seen the tympanic membrane of the frog on the outer sur- face of the head. The function of the tym- panic membrane is to receive sound waves, for all sound is caused by vibrations in the air, these vibrations being transmitted, by the means of a com- plicated apparatus found in the middle ear, to the real organ of hearing located in the inner ear. Middle Ear.— The middle ear in man is a cavity inclosed by the temporal bone, and separated from. Section of ear, showing auditory canal, middle ear, internal ear, and Eustachian tube. the outer ear by the tympanic membrane. A little tube called the Eusta- chian tube connects the inner ear with the mouth cavity. By allowing air to enter from the mouth, the air pressure is equalized on the ear drum. For this reason, we open the mouth at the time of a heavy concussion and thus prevent the rupture of the delicate tympanic membrane. Placed directly against the tympanic membrane and connecting it with another mem- brane, separating the middle from the inner ear, is a chain of three tiny bones, the smallest bones of the body. The outermost is called the /jam- mer; the next the incus or anvil; the third the stirrup. All three bones are so called from their resemblances in shape to the articles for which they are named. These bones are held in plac
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