56. The arteries are so named because the air, that is, the breath, is carried by them from the lungs; or because they retain the breath of life in their narrow and close passages, whence they emit the sounds of the voice, which would all sound alike if the movement of the tongue did not create differences of the voice.
77. Lac (milk) derives its name from its color, because it is a white liquor, for the Greeks call white λεῦκος and its nature is changed from blood; for after the birth whatever blood has not yet been spent in the nourishing of the womb flows by a natural passage to the breasts, and whitening by their virtue, receives the quality of milk.
86. Ossa (bones) are the solid parts of the body. For on these all form and strength depend. Ossa are named from ustus (burned), because they were burned by the ancients, or as others think, from os (the mouth), because there they are visible, for everywhere else they are covered and concealed by the skin and flesh.
92. Terga, because it is on the back that we lie flat on the earth (terra); men alone can do this, for dumb animals lie either on the belly or on the side; whence the word tergum is applied to them mistakenly.
108. The knees are the meeting-points of the thighs and lower legs; and they are called knees (genua) because in the womb they are opposite to the cheeks (genae). For they adhere to them there and they are akin to the eyes, the revealers of tears and of pity. For the knees (genua) are so called from the cheeks (genae).
109. In short they assert that man in his beginning and first formation is so folded up that the knees are above, and by these the eyes are shaped so that there are deep hollows. Ennius says: “Atque genua comprimit artagena.” Thence it is that when men fall on their knees they at once begin to weep. For nature has willed that they remember their mother’s womb where they sat in darkness, as it were, until they should come to the light.
118. Cor is derived from a Greek term—what they call καρδία (heart)—or, it may be, from cura (cure). For in it dwell all anxious thought and wisdom. And it is near the lungs for this reason, that when it is fired by anger it may be cooled by the liquid of the lungs. It has two arteries, of which the left has more blood, the right, more air. From it also is the pulse we find in the right arm.
120. The pulsus (pulse) is so called because it beats (palpitet), and by its evidence we perceive that there is sickness or health. Its motion is two-fold; a simple motion which is made up of a single beat, and a composite, made up of several movements—irregular and unequal. And these movements have definite limits....
121. The veins are so called because they are the passages of the flowing blood, and its streamlets spread through all the body, by which all the parts are moistened.
124. The Greeks call the lungs πλεύμων, because they are the bellows of the heart and in them is πνεῦμα, that is, spiritus, by which they are stirred and moved, whence they are called pulmones....