Under varying aspects of the question of right-handedness the inquiries into its origin have naturally reverted to the lateral position of the heart as a probable source of diversity of action in the two hands; and this is the more suggestive owing to the fact that exceptional cases of its reversed position are occasionally found. When Carlyle reflected on right-handedness as “probably the oldest human institution that exists,” he suggested as the source of choice of the hand that it “probably arose in fighting: most important,” as he says, “to protect your heart and its adjacencies, and to carry the shield on the hand.” This idea, in so far as it implies the habitual use of the shield in the left hand, or on the left arm, and consequently of the shield-hand as left and passive, is old as Homer; and the evidence of its practice is abundantly confirmed by the drawings on the most archaic Greek vases. The right side was ἐπὶ δόρυ, the spear side, while the left was ἐπ’ ἀσπίδα, the shield side. The familiar application of the terms in this sense is seen in Xenophon’s _Anabasis_, IV. iii. 26: Καὶ παρήγγειλε τοῖς λοχαγοῖς κατ’ ἐνωμοτίας ποιήσασθαι ἕκαστον τὸν ἑαυτοῦ λόχον, παρ’ ἀσπίδας παραγαγόντας τὴν ἐνωμοτίαν ἐπὶ φάλαγγος, “He ordered to draw up his century in squads of twenty-five, and post them in line to the left.” And again, _Anabasis_, IV. iii. 29: Τοῖς δὲ παρ’ ἑαυτῷ παρήγγειλεν ... ἀναστρέψαντας ἐπὶ δόρυ, κ.τ.λ., “He ordered his own division, turning to the right,” etc. Egyptian paintings are older than the earliest Greek vases, but they are less reliable; for in the symmetrical arrangements of hieroglyphic paintings the groups of figures are habitually reversed, right and left, looking toward a central line or point. Yet there also evidence may be found confirming the same idea.