"Guilty of manslaughter in the first degree" was the verdict of a 9-woman, 3-man jury last night as the 3-week trial of Donald J. Langlois, charged with second degree murder in connection with the Dec. 31 death of his wife, came to an end at the Fulton County Courthouse, Johnstown.

The defendant, a 62-year-old resident of 155 South Kingsboro Avenue, Gloversville, was tried on the basis of a January indictment accusing him of striking his 55-year-old wife, Arlene, in the head several times with a hammer, then placing her body in a car trunk where she subsequently died. Hours later, he married Mrs. Christine Floyd of Gloversville RD 2 at the Broadalbin United Methodist Church.

Tension filled the air at 9:45 last night in the Johnstown courthouse, as the 12 jurors filed into the jury box after four hours and 40 minutes of deliberations yesterday in the case which took 14 full days to complete.

Approximately 80 spectators were present in the gallery when they returned to the main courtroom, where jury foreman Mrs. Alberta Cole of Johnstown told County Judge Carrol S. Walsh Jr., who presided, the unanimous verdict of the panel. A whisper ran through the crowd as the jury's decision was announced.

The defendant, attired in a brown sports jacket and checked pants, showed no visible signs of emotion as the verdict of the dozen jurors was revealed, a few moments later simply removing his glasses and closing his eyes.

Yet, as Judge Walsh was thanking the jurors and the two alternates for their attention and service in the case, Atty. George E. Abdella, his defense counsel, motioned to Undersheriff Thomas Daggett, who came over to the defense table to assist the defendant in a premature exit from the courtroom.

Langlois, rising from his chair, stumbled and began to collapse, but both Daggett and Sheriff Robert Wandel caught him, as two other deputies of the Fulton County sheriff's department helped carry the pale, obviously shaken defendant from the courtroom. It was the second time in just over three hours such an incident had occurred.

Judge Walsh, after excusing the jury and alternates, set 9:30 Friday morning, June 24, as the date for sentencing in the case, since the necessary pre-sentence investigation report had not been prepared. In the meantime, he was remanded to the Fulton County Jail, where he has remained without bail since his arrest Jan. 4 in Florida and return to New York state.

The maximum sentence for first-degree manslaughter in this state is 25 years in prison. When asked about the possibility of appeal, Atty. Abdella said he planned to confer with his client on the matter, but one is expected.