Do jazz solos have to be improvised? - Overthinking Old Jazz Episode 4

I’m a musician specialising in 1920s and 30s jazz and popular music, but I also used to be an English Literature teacher, so I love overanalysing things and listening to myself talk. ’Overthinking Old Jazz’ is a series designed to allow me to do all those things at once. In this thrilling instalment, I compare and contrast two clarinet solos by William Thornton Blue from different takes of Cab Calloway’s ’Happy Feet’, and use them as the basis for a discussion of whether or not jazz solos need to be improvised. Many thanks to Dave Bock for providing the transfer of the alternate take, which I only heard for the first time last week. By the way, these solos were tricky to transcribe, but I got them pretty close before giving up - as poet Paul Valéry wrote of poems, jazz solo transcriptions are never finished, only abandoned. Note-heads that appear as crosses indicate ’guesstimation’. All expenses have been spared in the making of this video.