With 56 cases contracted by students so far, pneumonitis, mysterious new infectious discase, has returned to the University after an absence of three years, Dr. Arlie V. Bock, head of the Hygiene Department, said yesterday.

Hitting the College in July, the disease has been the biggest headache of the University Health officials for several months. It attacked with the same severity in the winter of 1938-1939, when about 83 students contracted the ailment.

Although 25 percent of the illnesses in the University this week are pneumonitis attacks, Bock said, the disease will probably not reach a stage of the proportions of the 1928 influenza epidemic. It is increasing daily, however, and its future occurrence is still unpredictable.

Discase Rarely Deadly

Although pneumonitis, unlike the similar "true influenza" of 1918, is deadly in only a few isolated cases, Bock added, it is a very unpleasant thing to have, and it can be avoided. Students should live wisely, he said, avoid the sudden changes in temperature, such as the trip from the "fright Stadium to the warmth of a room flowing with cocktails" which so many students made last Saturday.

If the students can keep up their resistance, avoiding the same things that they have been taught to avoid in order to keep from catching cold, the disease may very possibly be wiped out or considerably reduced before reaching too great proportions, he said.

Extremely difficult to detect, pneumonitis is easily confused with the common cold with very similar symptoms in its early stages. In later stages it is accompanied by a fever and the characteristic lung condition of all pneumonia types.

There is no medical treatment for the disease except careful nursing and hospitalization, Bock said. It may last from several weeks in those of College age, to months in older people, though if the discase is caught early it is usually of shorter duration.