Hergesheimer, in reverie, discovers Nabokov ailing on a Swiss slope, slipped or tripped in pursuit of a butterfly, boyishly bare-kneed in old-man baggy shorts, unable himself to rise. Lean on me, says Hergesheimer, balancing, bracing, taking the aged fellow’s fortunately downhill considerable weight. It’s not far, he reassures them both. Nearly there. Stop if you need to rest. Hergesheimer can see already his sporty red Peugeot only a few steps more, has the door for Nabokov open at once, hurries the passenger seat to its furthest back position—big man, little car—assists, composes, folds and fits the full measure of largely…