1. 
No, no! go not to Lethe, neither twist  
Wolf's-bane, tight-rooted, for its poisonous wine;  
Nor suffer thy pale forehead to be kissed  
By nightshade, ruby grape of Proserpine;  
Make not your rosary of yew-berries,  
Nor let the beetle nor the death-moth be  
Your mournful Psyche, nor the downy owl 
A partner in your sorrow's mysteries;  
For shade to shade will come too drowsily,  
And drown the wakeful anguish of the soul. 
 
2. 
But when the melancholy fit shall fall  
Sudden from heaven like a weeping cloud,  
That fosters the droop-headed flowers all,  
And hides the green hill in an April shroud;  
Then glut thy sorrow on a morning rose,  
Or on the rainbow of the salt sand-wave,  
Or on the wealth of globed peonies; 
Or if thy mistress some rich anger shows,  
Emprison her soft hand, and let her rave,  
And feed deep, deep upon her peerless eyes. 
 
3. 
She dwells with Beauty - Beauty that must die;  
And Joy, whose hand is ever at his lips  
Bidding adieu; and aching Pleasure nigh,  
Turning to poison while the bee-mouth sips;  
Ay, in the very temple of delight  
Veiled Melancholy has her sovran shrine,  
Though seen of none save him whose strenuous 
tongue 
Can burst Joy's grape against his palate fine;  
His soul shall taste the sadness of her might,  
And be among her cloudy trophies hung.
John Keats
http://www.poemhunter.com/poem/ode-on-melancholy-2/