  The validity of the Bianchi identity, which is intimately connected with the
zig zag symmetry, is established, for piecewise continuous contours, in the
context of Polakov's gauge field-string connection in the large 'tHooft
coupling limit, according to which the chromoelectric `string' propagates in
five dimensions with its ends attached on a Wilson loop in four dimensions. An
explicit check in the wavy line approximation is presented.
