Muskie Assumes Populist Stance In Wis. Primary

SHEBOYGAN, Wis.--The Wisconsin Primary campaign continued to heat up yesterday as the major contenders vigorously plunged into the final week of speeches and handshaking before Tuesday's balloting.

Observers here are rating the race a toss up between Humphrey, Muskie and McGovern. Because he may be helped by Republican cross-over votes, George Wallace's performance is impossible to predict.

At stake are all 67 delegates to the Democratic convention. Some observers rate Humphrey a slight favorite because his home state, Minnesota, is a bordering