Jubilate Agno by Christopher Smart.
Thanks to Ray Davis, the blogger at Pseudopodium, we have an online publication of the Jubilate Agno fragments, an eighteenth-century poem that usually never sees the light of day unless an anthology decides to publish an excerpt. When they do it's always the same excerpt. Sometimes they call this excerpt My Cat Jeoffrey - you know -
For I Will Consider My Cat Jeoffry
For he is the servant of the Living God duly and daily serving him
For at the first glance of the glory of God in the East he worships in his way.
For is this done by wreathing his body seven times round with elegant quickness.
- and "spraggle upon wraggle," and so on. Jeoffrey can be found at the end of Fragment B, part 4 of the Agno, if you're curious. Smart wrote the poem between 1757 and 1763 after he had suffered a breakdown and been confined to a lunatic asylum. The nature of this breakdown is not exactly known, but it seems to have manifested itself in excessive public praying. "My poor friend Smart shewed the disturbance of his mind, by falling upon his knees, and saying his prayers in the street, or in any other unusual place," said Samuel Johnson. In an extensive biography and evaluation of Smart's work at the Poetry Foundation website, Karin Williamson points out that this account is supported by lines in the poem itself:
For I blessed God in St James's Park till I routed all the company.
For the officers of the peace are at variance with me, and the watchman smites me with his staff.
Jubilate Agno, even in its fragmentary form, is Smart's "prophetic book": a doxology, evangelical and philosophical manifesto, personal diary, and commonplace book all in one, as well as a remarkable experiment in poetic form. On internal evidence, it appears to have been written over a period of four to five years, from 1758-1759 to 1763. The manuscript, whose existence was not publicly known until 1939, consists of two sets of loose papers, each set containing closely written series of verses all beginning with the same word--Let and For, respectively.
There's a long article about his confinement at Wikipedia, along with a Smart biography, which is supplemented with links to other articles about his georgic The Hop-Garden, mock-epic The Hilliad, and other works. Williamson, in her piece, takes a look at the other major poem he wrote during his incarceration, A Song to David. "I have seen his Song to David and from thence conclude him as mad as ever," remarked one of his friends to another, although anyone who puts Agno next to the more conventional rhyming David is likely to wonder what he was getting excited about. If "The spotted ounce and playsome cubs / Run rustling ’mong the flowering shrubs" was enough to make this friend conclude that he was mad then Smart should be glad he never got to Agno's depilated Sodomites, or the "Sea-Horse, who shoud have been to Tychicus the father of Yorkshiremen" or
Let Demetrius rejoice with Peloris, who is greatest of Shell-Fishes.
Let Antipas rejoice with Pentadactylus -- A papist hath no sentiment God bless CHURCHILL.
Looking at Agno next to the rest of his output reminds me of the time I came across Milton unexpectedly in John Hayward's anthology of seventeenth century poetry and saw - for the first time, because till then I'd only seen him among other poets considered Great, where his presence was ordinary and expected - how vividly he ripped through his contemporaries, how, in the middle of a field of Phyllisses and perishing roses he seared like a lightning bolt. The Agno is not Milton, but it is marvellous and unusual.
Then there's a short piece about the Jeoffrey excerpt at Slate, by Robert Pinsky, and a Smart essay available by someone - a university student? - named Ross King, Insolent Women and Crest-fallen Men: Christopher Smart, The Midwife, and Literary Travestism. Parts of The Midwife magazine (one of several that he wrote for during his lifetime) can be read at Google books.
Let Jether, the son of Gideon, rejoice with Ecchetae which are musical grashoppers.