The cause of last week's vomiting epidemic will not be known until next month, Director of Dining Services Michael P. Berry told the Undergraduate Council last night.

Berry said the illness was most likely either the result of a virus or an unknown toxin carried in the air. But the exact cause remains uncertain, and tests on students who became ill last week will continue for another month.

"We won't know anything definitely until January because we're testing for toxins in the convalescent period," he said.

Berry's comments came as a number of students around campus reported suddenly experiencing symptoms similar to those of the hundreds of undergraduates afflicted last Tuesday night and Wednesday morning. The symptoms include nausea, severe vomiting and diarrhea.

Dr. David S. Rosenthal '59, the director of the University Health Services, said yesterday that between six and a dozen students have been admitted to the health service during each of the last two days. But he said it is not clear whether the illnesses of the newly sick are related to the epidemic of Tuesday night.

"It's difficult to say if this is the same or if it's the background gas- troenteritis that goes with the winter," Rosenthal said.

Both Berry and Rosenthal said that tests on food in the Union have found no evidence of any bacterial contamination. That finding has increased speculation that the source of any problem is viral.

"We have completed all tests on the Freshman Union food and food handlers," Berry said. "There is no evidence that this was a food-borne illness. The illness was more likely viral. Originally food seemed the most logical source of the epidemic to me, but since then we've been ruling it out."

But Berry has not ruled out the remote possibility of food-borne contamination coming from the salad bar. He suggested the possibility of airborne toxins being spread via the salad bar.

"If we are looking at one particular area, it's the salad bar," he said. "Every other food item has come back clean of toxins and bacteria."

Berry singled out the eggs and cold pasta offered in the salad bar as possible, though unlikely, culprits. "You'll notice that we pulled both items in the houses," Berry said. "However, there's no indication that people got sick from them."

Berry praised the way the University has responded to the situation. "The state inspectors said it was the best protocol they've seen," he said.

Cameras from Channel 7 were at the meeting.

According to a University statement released over the weekend, Stillman Infirmary treated approximately 225 reported cases of the gastrointestinal illness between Tuesday and yesterday.

Usually, Stillman treats no more than four people per day for gastrointestinal illnesses, the statement said. The majority of these sicknesses are caused by food-corne contaminants.

Despite Berry's hopes for identifying the cause, however, the statement cautioned that the source of gastrointestinal illness often cannot be determined.