The official enrollment of Chemistry 20, "Organic Chemistry," has dropped from about 470 to 375 this spring. More than ten per cent of the students who took the mid-year exam were required to withdraw because they received grades of D or E.

The grade received in organic chemistry is generally considered to be one of the most important factors in a medical school's evaluation of an applicant. Chem 20 is the only introductory organic course in the College.

Of the approximately 440 students who took the four-hour midyear exam, at least 48 received grades of D or E and were forced to drop the course. About 65 students with grades of C- were urged to consider withdrawing from the course, Weston T. Borden, associate professor of Chemistry, said yesterday.

This term, Borden will replace one of the two Chem 20 professors, David H. Dolphin, associate professor of Chemistry, who is leaving the University.

Am I My Brother's Keeper?

Many students were upset that the grades of every student were posted outside of the office of the other Chem 20 professor, William Doering, Mallinckrodt Professor of Chemistry.

Borden said he may not use this procedure for his own lecture section this June. "At the moment, I have no plans to post the grades," he said. He said he plans to distribute answer sheets immediately after the final, and that he will permit students to see their exam papers when they have been graded.

There was widespread dissatisfaction with the reduction of the number of teaching fellows allotted to one of the two lecture sections. This spring, Doering will teach the more difficult lecture section, composed mostly of about 75 students who received grades of B+ or above at mid-year. These students will not be assigned to a regular teaching fellow, but will be allowed to attend sessions with some teaching fellow about once a week to discuss their problems with the course.

Students in the less difficult section, taught by Borden, will be assigned to a particular teaching fellow.

Grignard Reaction

"I think they should have sections. It's a terrible way to economize," Pamela I. Hartzband '74, a student in the more difficult Chem 20 section, said yesterday.

L.G. Wade Jr., head lab teaching fellow of Chem 20, said yesterday that the Chemistry Department did not have enough graduate students or money to hire more teaching fellows. "We don't have enough people in the department to make sections small enough," he said.

Elimination Reaction

Many students in the course considered the grading too stiff.

"I think they've made the course too competitive. For the amount of time people put into the course, the median should not have been C+. I think they foster the atmosphere of competitiveness," D. Jill Joyce '75, a Chem 20 student, said yesterday.

Borden will try to grade his section this Spring fairly, he said yesterday. "People will get what they deserve. I'm not setting the median. It will depend on the performance of the group. The graduate course I taught this fall had an A-median," he said.

Steric Hindrance

Several teaching fellows said they were disturbed that they were not consulted to help decide grades in borderline cases, as Chem 20 professors have done in the past.

"Participation in determining borderline cases was minimal or non-existent," one teaching fellow said yesterday.

Doering refused to comment and Dolphin could not be reached