A Pittsburgh, Pa., pathologist testified yesterday in Boston that the fetus Dr. Kenneth C. Edelin is accused of killing breathed before it died, and Edelin's defense quickly sought to discredit the witness.

Dr. John F. Ward said that slides of a cross-section of lung tissue from the dead fetus revealed a "lack of uniformity" in the expansion of the air spaces, which he said was evidence of respiration of air by the fetus.

Prosecution testimony continued yesterday as Judge James P. McGuire declined to rule on a defense motion to dismiss the case until he has read recent U.S. Supreme Court rulings concerning the issue.

The defense contends that there was unconstitutional discrimination against women in selecting the grand jury that returned the Edlin indictment.

Edelin is charged with manslaughter in Suffolk County Superior Court in connection with a hysterotomy operation he performed on a pregnant woman on October 3, 1973, at Boston City Hospital.

Prosecutor Newman A. Flanagan, assistant district attorney, alleges that Edelin allowed a "male child" to be born "detached from the mother" in the course of that operation, and then permitted it to die.

The prosecution is expected to rest its case today.

Under examination by Flanagan, Ward testified that in a stillborn fetus air cells in the lung are uniformly expanded with fluid secreted by the lungs.

Up for Air

Ward said that slides of lung tissue from the fetus involved in the Edelin case displayed collapsed, partially-collapsed and expanded alveoli, or air spaces. He concluded that the state of the lung cells was due to respiration of air by the fetus before it died.

William P. Homans Jr. '41, Edelin's attoney, was developing an intense criticism of Ward's argument when McGuire recessed his court at 4 p.m.

Homans established that a fetus undergoes "distress" when the placenta, its connection to the mother, is separated from the uterus, and that under such distress a fetus might begin to inhale and exhale the amniotic fluid that surrounds it within the amniotic sac.

In the involved hysterotomy operation, Edelin cut the uterus, then used his hand to separate the placenta from the uterine wall.

Ward resisted Homans's efforts to establish that the presence of fluid in the lungs was due to inhalation of amniotic fluid.

However, Ward acknowledged under cross-examination that he could not be sure that the fluid in the lungs was secreted by the lungs, as he indicated initially.

Ward explained that his conclusions were based on an examination of slides, and that such investigation did not permit analysis of the chemical content of the fluid within the alveoli.

The Pittsburgh University-educated pathologist also testified that the fetus died 26 weeks after it was conceived. The prosecution claims that the fetus was between 24 and 28 weeks old and could have lived if delivered at the time of the hysterotomy.

Homans objected to this testimony by Ward because he said that a pathologist is not qualified to give expert evidence on matters involving obstetrics and gynecology. He was overruled.

However, during cross-examination in the afternoon session yesterday, Homans picked at Ward's testimony, suggesting that he had confused his standards for measuring fetal age, and that the estimate of 26 weeks was exaggerated.

Seemingly impatient with the witness, Homans addressed Ward as "sir" or even "mr. witness," while prosecutor Flanagan always addressed him as "doctor."

Crown to Rump

Homans showed that a table of "crown to heel," or head to toe, fetal measurement that the pathologist had testified was to be found in a certain scientific paper could not in fact be found there. That paper did include a correlation of "crown to rump" fetal measurement with certain fetal ages.

Measurements of the length and weight of the fetus in the Edelin case were made in an autopsy four months after the operation, but Ward questioned the accuracy of the weight measurement.

Dry Run

He said that the preservation of the fetus in Formalin, a liquid solution of formaldehyde, dehydrated the fetus so that it weighed less at the autopsy than it did at the time of the operation.

Homans cited a list of scientific papers on the effect of preservation in Formalin on tissue weight and, after establishing that Ward was familiar with none of them, suggested that the doctor was not qualified to speculate on the age of the fetus.

The defense attorney implied that Ward had employed standards of measurement in interpreting figures from the autopsy that would yield a contrived and exaggerated estimate of the age of the fetus.

Ward, a balding and bespectacled man who wore a conservative gray suit and a plain white shirt, remained calm during examination by Flanagan, who said yesterday that he travelled to Pittsburgh two months ago to confirm that Ward would testify.

However, during Homans's barking cross-examination, Ward seemed non-plussed and often gave rambling answers to questions about apparent contradictions in his testimony.

Ward was preceded on the stand by Dr. Joseph Kennedy Jr., a neonatologist--a scientist dealing with newborn children under 28 days old.

Kennedy testified that Edelin performed the abortion 24 weeks after conception. "The subject was 'viable,'" Kennedy said, "in that he had a chance for survival for a long period of time."

Homans asked for a more specific definition of "chance for survival" and Kennedy testified that if there was a one in 500 chance that the fetus could have survived, it was viable.

Flanagan immediately stood up and asked if this definition of viability also applied to a fetus that faces a "two-to-one" prospect of survival. Kennedy said that it did.

Yesterday's day in court began with a hearing to determine whether Flanagan could introduce as witnesses mothers of babies that had been delivered prematurely.

McGuire ruled that Flanagan could not produce these witnesses.

Flanagan said that the introduction of witnesses that at delivery were "younger than this particular subject, smaller than this particular subject, and weighed less than this particular subject" would show that the fetus in the Edelin case was indeed viable.

"These are only possible cases," Homans said. "Isolated incidence of survival should not lead anyone to expect that any given fetus should survive."

McGuire agreed that such a presentation would be "evidence of similar but unrelated events."

Homans also argued, "The only thing the jury gains from seeing the baby in the courtroom is seeing it kick or laugh or cry. The baby can't testify as to its gestational age.