spirit (n.) 3
life-supporting substance thought to be carried by the blood, animating essence
2H4 IV.iii.108 [Falstaff alone, of the effect of sherry on the body] the vital commoners, and inland petty spirits, muster me all to their captain, the heart
TC I.i.59 [Troilus to Pandarus, of Cressida's hands] to whose soft seizure / The cygnet's down is harsh, and spirit of sense / Hard as the palm of ploughman!
TC III.iii.106 [Achilles to Ulysses, of the eye] That most pure spirit of sense
See also...
vital (adj.)