Over 90 percent of the people in this country either have had some form of polio or are carrying the virus in their systems. The reason why some are crippled by the disease upon exposure and others show no effect is one of the projects under research at the Medical School and the School of Public Health.

Harvard's School of Public Health, where the first iron lung was developed more than 20 years ago, is the birthplace of a new discovery to aid polio victims--the electric lung. By electric impulses, this device causes the diaphragm to contract, thus filling the lungs.

These machines are only two of the many contributions the School of Public Health and the Medical School have made to the fight against infantile paralysis.

Laboratory men are growing polio virus in human tissues, hoping eventually to find a vaccine against the germ. Researchers have discovered ways to immunize mice partially. Other doctors are finding new means to help victims walk again by surgery and exercise, while psychologists are watching the effects on patients of living in an iron lung. The likeliness and control of epidemics are also getting attention. Nearly every phase of polio is being studied at the University.

The electric lung, formally known as the electrophrenic respirator, was perfected by two men in the Physiology Department of the School of Public Health, Dr. James L. Whittenberger and Dr. Stanley J. Sarnoff.

Most often applied externally to the neck, it electrically imposes its own breathing pattern on the nerves controlling the diaphragm. The machine can be plugged into any household socket and is light enough to be carried right to the bedside of a patient.

The EPR is not meant to replace the iron lung because it is mainly effective against only one type of polio--bulbar polio. This variety of the disease attacks the bulb at the base of the skull where the nerve center is located. The EPR takes over for the disturbed nerve center and substitutes its own steady breathing impulses for the weak, irregular ones from the brain.

Sarnoff conceived the idea while assisting at an operation at the Massachusetts General Hospital three years ago. The surgeon performing the operation accidentally touched the phrenic nerve, causing the patient's diaphragm to contract. Sarnoff wondered why this couldn't be done artificially to cause regular breathing and took the idea to Whittenberger who was studying the respiration of polio victims. Together they developed the electric lung.

The idea was not original, but Sarnoff and Whittenberger did not know this until a few months ago. Someone then referred them to a book, printed in 1861 in England, which describes the method with crude apparatus.

The two doctors had to find the exact spot on the neck where the device could be applied with the greatest success. Sarnoff's wife, also his laboratory assistant, served as a human guinea pig, and the doctors spent hours probing her neck with the electrode before they were successful.

The National Foundation for Infantile Paralysis, which gives most of the funds for University research on polio, contributed money to this project at its birth and recently provided $23,000 to the department for further work on respiration.

The first iron lung was also conceived and invented by a man in the School of Public Health, Phillip Drinker, head of the Department of Industrial Hygiene. Over 20 years ago, Drinker was watching a colleague, Louis A. Shaw, perform experiments to measure the amount of air a cat held in its lungs after a normal breath.

Leads to Development of Iron Lung

Shaw had the cat in an air-tight box, with its head sticking out of a rubber collar in the side. There was a guage attached to the box, and when the cat inhaled--expanding its lungs--the air in the box would be compressed and would cause the guage's pointer to rise. As the cat exhaled, there would be a partial vacuum in the box, and the pointer would fall.

Why, thought Drinker, can't we reverse the process? First, push air into the box to press on the lungs, making the cat exhale, and then draw air out of the box, causing air to rush into the lungs and fill the vacuum. The two men got to work at once and soon were making the cat breath mechanically by pumping air into and out of the box.