The title is deceptive because this study actually explores the seven tonalities in which C occurs as chord tone (From bII (D flat) to V (G) .
Therefore it’s an etude on modes with C as tonic.
the principle is motive 
reworked with a new alteration down to five flat or up to one sharp.
This principle applies to different figures, different articulations and variegations
on every register
or
To avoid monotony each motive is not systematically tranposed in all modes; the goal of this study being a mean to review the main clarinet difficulties in a short time and a warming up tool.
