MIDDLETOWN, Conn. — When a Wesleyan University student who had taken drugs at a party last month began feeling ill, his friends took him to his dorm room, gave him water and Triscuits, and assumed he just needed to sleep it off.

A few hours later, he sat up in bed, gasping for air, then collapsed back onto his mattress, unconscious and not breathing.

As an ambulance raced to the dorm room, the first of eight similar runs at the university that would take place over the course of the day, dispatchers coached the student’s friend on how to perform chest compressions. After more than 150 compressions from the friend and from medics, six shocks with a defibrillator and an intubation, the student was taken to a hospital and survived.

But the frenzy of that day has jolted Wesleyan University, a prestigious liberal arts university of around 2,900 students in central Connecticut. After taking what has been described as a bad batch of Molly, a widely used club drug, on the night of Feb. 21, 10 students and two guests were taken to hospitals or went there on their own. Administrators became so alarmed that a vice president sent a campuswide email exhorting students to check on their friends to make sure they were O.K., adding: “Do this right now!”