Allen Gartner, head of the Boston chapter of CORE, admitted Sunday that there is no concrete evidence of actual discrimination by the Hayes-Bickford Cafeterias, and said the July 10 demonstration outside the Cambridge Bick was not meant to imply that there was.

He said, however, that the demonstration was prompted by "had faith" on the part of the Bick management in negotiations with CORE officials.

As early as November, Gartner said, CORE had complained that of the 500 persons employed by the restaurant chain, "considerably less than 20 were Negroes."

A study made in June showed the situation had hardly changed, Gartner said, although the Hayes-Bickford management "kept indicating to our people between November and June that they were actually seeking Negroes and actually increasing the number employed. They gave us various numbers."

Gartner said he was "not terribly concerned with overt discrimination." He observed that the low number of Negroes employed tends to "build up a rigid system." This is so, he said, since many employees obtain jobs through people who already work at the Bick, and because Negroes are discouraged from applying for a job when they see that most of the employees of an establishment are white.

Gartner said that CORE's aim was that the Bick make a concerted effort to attract more Negro employees. Merely not to discriminate is not enough, he said.