Thare iz plenty ov happiness in this life if we only knu it: and one way tew find it iz, when we hav got the old rumatiz tew thank Heaven that it aint the old gout.

[There is plenty of happiness in this life if we only knew it: and one way to find it is, when we have got the old rheumatism to thank Heaven that it ain’t the old gout.]

Josh Billings (1818-1885) American humorist, aphorist [pseud. of Henry Wheeler Shaw]

Everybody’s Friend, Or; Josh Billing’s Encyclopedia and Proverbial Philosophy of Wit and Humor, ch. 137 “Affurisms: Tadpoles” (1874)
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In Fred Lewis Pattee, A History of American Literature Since 1870 (1915), this is paraphrased "The best cure for rheumatism is to thank the Lord it ain't the gout."

In a similar vein, in Josh Billings' Old Farmer's Allminax, 1870-1879, January 1878, "Chips" (1902):

The best relief for the rumatiz, that haz been diskovered yet, iz to find sum phellow who haz got the gout bad, and then pitty him.

[The best relief for the rheumatism that has been discovered yet is to find some fellow who has got the gout bad, and then pity him.]

and in H. Montague, ed., Wit and Wisdom of Josh Billings (1913)

The best remedy for RHEUMATISM that's ever yet been discovered is to find some fellow who has a bad case of the gout, pity him and forget yourself.