  When $N$ five-branes of M-theory coincide the world-volume theory contains
tensionless strings, according to Strominger's construction. This suggests a
large $N$ limit of tensionless string theories. For the small $E_8$ instanton
theories, the definition would be a large instanton number. An adiabatic
argument suggests that in the large $N$ limit an effective extra uncompactified
dimension might be observed. We also propose ``surface-equations'', which are
an analog of Makeenko-Migdal loop-equations, and might describe correlators in
the tensionless string theories. In these equations, the anti-self-dual two
forms of 6D and the tensionless strings enter on an equal footing. Addition of
strings with CFTs on their world-sheet is analogous to addition of matter in 4D
QCD.
