Experimental cadavers have become scarce commodities at the Medical School, the Department of Anatomy reported yesterday. And unless appropriate legislation is passed, the school's standard of anatomical instruction is in danger.

This follows a national trend of falling supply of experimental bodies even in prominent medical schools. G.I. benefit laws and social-welfare measures are to blame, the department explained.

Under normal circumstances freshman anatomy students dissect two bodies in their first year, but with this current shortage, the limit has been cut to one per year. Forty-five specimens are used annually, with four men dissecting one body.

The department reports that if the ratio increases to five and six men per cadaver its standards may fall.

Cadavers come from three principal sources: inmates of state institutions without family; vagrants; and bequests. Since an increasing number of American males come under G.I. rights, which entitles them to a free burial, thousands of otherwise perfectly acceptable cadavers lie in cemeteries instead of on the experimenting table. These G.I. laws state that no veteran of the Civil War or any foreign war may be dissected.

So far, only nine states, excluding Massachusetts, permit persons legally to bequeath their bodies for experimental purposes.

To handle the shortage, Harvard, Tufts, and Boston University share their supplies of cadavers in a reciprocal arrangement.