The movie industry is like a cat with a mouse. Once the moviemen get a successful idea; they go on playing with it until they have killed it.

"Jolson Sings Again," is a prime example of their handiwork. "The Jolson Story," to which the present effort is a lame sequel, made very good business for the box offices when it came out two years ago; a movie about the "mammy" singer of the twenties, with Al Jolson's voice on the sound track, was almost a sure thing from the start. But there were a few of Jolson's top numbers that couldn't be fitted in. When the film turned out to be a hit, the moviemakers couldn't resist the temptation to have Jolson sing again.

The story picks up where it ended in the first film--with Jolson's first wife leaving him because he preferred his career to her. Unfortunately, most of the interesting material had been used up in the first film, and as a result the sequel's plot is pretty pallid. Jolson, torn between the desire to return to the stage and the feeling that his time has passed, moons about despondently while the rest of the cast worries out loud about him and tells him he ought to relax.

All this doesn't make for much opportunity for Jolson to sing. Eventually, however, World War II intervenes, and he volunteers to entertain the armed forces. There are scenes of Jolson singing "Four Leaf Clover" in an Aleutian quonset hut and "Chinatown" under Tunisian palms; at length, he collapses with fever, and is flown home, where he falls in love with his nurse, (Barbara Hale).

After rallying and setting off on an entertainment tour of veterans hospitals--an opportunity to dub in "Sonny Boy" and "Toot-Toot-Tootsie" (among others) on the sound track--Jolson collapses again. Miss Hale, of course, appears at his bedside. Her lines are poor--she too has to spend her time telling Jolson to relax--but her performance is enough to make her a leading candidate for the worst actress of the year. Unfortunately she stays around to marry Jolson and manage his life.

Before you know it she has him in the movies--doing the songs for "The Jolson Story." There is a charming studio interlude where Larry Parks playing Al Jolson meets Larry Parks playing Larry Parks, and finally, the only redeeming feature of the whole piece, a scene of the premiere of "The Jolson Story."

This is a good excuse for Columbia to slip in some of the better parts of the original picture, including famous Jolson songs-like "Mammy" and "Swanee."

Except for the singing, the picture is a dead loss, and even the singing is marred by Larry Parks' stiff and unconvincing stage mannerisms and his way of ebbing and flowing behind the microphone. Ardent "mammy" fans may be able to endure the plot to hear the master sing--but they will have to be made of sterner stuff than I.