Thomas Hardy contrasts an old man's decaying body with a young man's potential to love with imagery related to the heart in "I Look Into My Glass".
He talks about how even when his skin has gotten old and his body shows old the aging signs his hart is still as young as any other and it is still capable of love and feel like the one in a young body.
Here is a little part of it
*I look into my glass,
And view my wasting skin,
And say, ‘Would God it came to pass
My heart had shrunk as thin!’
