The Love Song of Dr Watson uses quotations from a number of other songs, or, if you prefer, Dr Watson’s impassioned rendering in front of an open window back in the 1880s released into the ether a number of fragmentary literary and musical suggestions that were picked up decades later by lyricists and composers well attuned to the music of the cosmos.

-- Once I had a secret love / that lived within the heart of me, / but now my secret love’s no secret any more. - Once I had a secret love / Sammy Fain & Paul Francis Webster,  From Calamity Jane (movie) (1953), First two lines plus last line substituting but for and.
-- I’ve just meat a girl named Miss Jekyll, - Maria, From West Side Story / Lyrics by Stephen Sondheim, music by Leonard Bernstein (1957), Subsituting Miss Jekyll for Maria
-- sweeter than honey or treacle, - linking line following the melody of Maria more or less
-- and she’s the secret love that I adore. - Secret love / Fain/Webster (Calamity Jane, 1953)
-- Gertrude, her name is Gertrude,  - linking phrase
--  it's a grand old name, - Mary’s a grand old name / by George M. Cohan (1906)
-- and suddenly my life will never be the same - Maria / Sondheim/Bernstein (West Side Story, 1957), substituting my life for that name
-- I’m laughing at clouds, so dark up above, / the sun’s in my heart and I’m ready for love. - Singing in the rain, from the film Hollywood revue of 1929 / by Arthur Fireed and Nacio Herb Brown
-- I have often walked down that street before, / but the pavement always stayed beneath my feet before. - On the street where you live . From My fair lady / lyrics Alan Jay Lerner, music Frederick Loewe (1964)
-- Suddenly I’m - link
-- somewhere over the rainbow, / way up high, - Somewhere over the rainbow. From The Wizard of Oz (1939) Music by Harold Arlen, lyrics by E.Y. Harburg
-- watching the clouds and rain go, / watching them all go by - Link
-- The sun has got his hat on, so shout hip hip hooray, / the sun has got his hat on and he’s coming out to play. - The sun has got his hat on. From Me and my girl (1937). Lyrics Arthur Rose and Douglas Furber, music Noel Gay
-- Love is a many splendored thing -  Popular song: music by Sammy Fain and lyrics by Paul Francis Webster (1955); used as theme song for the film Love is a many splendored thing (1955) and the soap opera based on the movie.
-- and it makes me feelbetter than any king - added linking line
-- Every minute I get bolder - MA! (He’s Makin’ Eyes At Me). Music: Con Conrad / Lyrics: Sidney Clare, 1921
-- there’s a bluebird on my shoulder, / it’s the truth, it’s actual - Zip-a-Dee-Doo-Dah, from the Disney film Song of the South (1946).  Music by Allie Wrubel, lyrics by Ray Gilbert.
-- Ahem – You see, Holmes, my account is entirely factual - Added linking line.
- You can call me a cock-eyed optimist - A cock-eyed optimist, from South Pacific (1949).  Music by Richard Rodgers, book by Oscar Hammerstein II.
-- but every day is like the first day of spring - “Every day would be the first day of spring” from If I ruled the world, throm the musical Pickwick.
    Words by Leslie Bricusse, music by Cyril Ornadel.
-- London’s enshrouded in a rosy mist … / oh how I wish I knew how to sing. / I hope, Holmes it happens to you. - Added linking lines
-- You’ve got to have a dream / if you don’t have a dream / how [the Dickens] can you have a dream come true - Bloody Mary’s song, You’ve got to have a dream, from South Pacific (1949).  Rodgers and Hammerstein.  “The Dickens” added.
-- G-G-G-Gertrude, beautiful Gertrude! - K-K-K-Katie, beautiful Katie: words and music by Geoffrey O’Hara (1918)
-- Now my secret love’s no secret any more - Once I had a secret love / Sammy Fain & Paul Francis Webster. From Calamity Jane (movie) (1953)