In my init file I have

(custom-set-variables
  . . .
   '(org-babel-lob-files
   (quote
    ("/home/hercynian/org/babeltest/a.org" "/home/hercynian/org/babeltest/
b.org")))

that, of course, lasted an Emacs reboot after I had set them with
customization. But then right after Emacs reboot, looking into the contents
of `org-babel-library-of-babel`, I do not see the "association list" of the
entire code blocks of a.org and b.org as I did in the last Emacs/org-mode
session when I ran `org-babel-lob-ingest` on a.org and b.org. So
`org-babel-library-of-babel` is populated only
through `org-babel-lob-ingest`. Next question was, Does code alive in the
current `org-babel-library-of-babel` make it live and ready to use?
Apparently not. Experimenting has shown that starting Emacs not only does
not auto-populate `org-babel-library-of-babel`, but even when I do
a `org-babel-lob-ingest` on a.org and b.org, SLIME takes no notice and
fails to see the functions in a.org and b.org.

Here's my `org-babel-library-of-babel`:

Value: ((multi_x2 "lisp" "(defun multi_x2 (x)\n  (* 2 x))"
           ((:comments . "")
            (:shebang . "")
            (:cache . "no")
            (:padline . "")
            (:noweb . "no")
            (:tangle . "no")
            (:exports . "code")
            (:results . "replace")
            (:session)
            (:hlines . "no"))
           "" "multi_x2" 0 18)
 (myadd "lisp" "(defun myadd (x y)\n  (+ x y))"
        ((:comments . "")
         (:shebang . "")
         (:cache . "no")
         (:padline . "")
         (:noweb . "no")
         (:tangle . "no")
         (:exports . "code")
         (:results . "replace")
         (:session)
         (:hlines . "no"))
        "" "myadd" 0 15))

which seems like my code block in c.org should know about them, right? No.
Again, Babel LOB seems to have forgotten to tell SLIME the good news. But
then maybe I need to say something specific in my add&multi_x2 code block
about these helper functions I've got in a.org and b.org?