Jacobson was as bewildered by the fast-moving events as was Bennett. Having joined the Penn faculty only a month earlier, he hadn't even finished unpacking his books.

It was the possibility of doing gene therapy research on RP that had attracted the shy, soft-spoken specialist to Philadelphia.

After having spent so many years with patients for whom he could do little, it was exciting for Jacobson to think that they might be on the verge of developing a treatment for this cruel disease.

Bennett, 40, and Maguire, 35, started experimenting with gene therapy in 1990, shortly after completing their medical training.

With practically no research money and working in a basement sink in the Beaumont Hospital in Royal Oak, Mich., the husband-and-wife team had few successes at first.

It wasn't until the summer of 1993, after Maguire became a surgeon at the Scheie Eye Institute and Bennett arrived at Penn, that things began to look up. Rather than working in a basement sink, she had use of the beautifully equipped labs in Scheie's F.M. Kirby Center of Molecular Ophthalmology.

And Wilson had just arrived at Penn, announcing that he was setting up the gene therapy institute and looking for projects. Having worked under him as a medical student when Wilson was an intern at Massachusetts General Hospital in Boston, Bennett sent Wilson an I-bet-you-don't-remember-me letter and a request for a get-together.

Wilson did remember her and was eager to talk about gene therapy. Huddling over a little wooden table in Wilson's office, the two spent an hour discussing the prospects of using it to treat eye disease.

Bennett explained how RP was actually many different genetic diseases, each caused by a defect in a different gene. Though probably dozens of genes are involved, most produce the same damage to the photoreceptor cells in the retina.

In humans, RP begins with poor night vision in childhood. The disease then strikes the periphery of the retina, covering photoreceptor cells with a black pigment that blocks light. The disease is named for these pigments.

As the damage slowly moves to the center of the retina, the patient develops tunnel vision that grows progressively narrow until the patient is completely blind, usually before the age of 50.

Bennett told Wilson that she thought the potential for treating RP with gene therapy was good because six RP genes had been identified.

She wanted to work with the gene that makes phosphodiesterase (PDE), an enzyme that helps turn light waves into neurological signals the brain can interpret. She wanted to work with PDE because some mice had defects in this gene, providing her animals with which to test the therapy.

Bennett wanted to inject viruses containing the PDE gene into the retina. The virus would infect the photoreceptor cells and deposit the PDE gene, which would start making the enzyme that RP patients lacked.

It was technically difficult since the eye of a newborn mouse is smaller than the tip of a ballpoint pen, but Maguire had no doubts that he could get the vector in.

Wilson was so impressed with Bennett's ideas and enthusiasm that he gave her the genetically altered viruses, or vectors, with which to experiment.

For two years, starting in the summer of 1993, the couple worked with Wilson's vectors, first testing them on photoreceptor cells in the test tube and then injecting them into the retina of mice. Since no one had ever done this before, there were many things to learn, such as when to treat the animals.

They thought the sooner the better since the disease quickly blinded the rodents, so they injected the mice immediately after birth. But the mothers kept eating their young because they had been touched by humans.

This didn't happen when the scientists waited until the animals were four days old - still enough time to start treatment since the disease didn't start destroying the retina until one week after birth.

RP blinds mice so quickly that Bennett would have been happy to slow down the process by even a few days. She wasn't prepared for what happened. The therapy prevented the disease, at least temporarily.