National Geographic : 1986 Jun
On Assignment THE SUBJECT WAS LIFE, though not exactly as we know it, when Sweden's Lennart Nilsson (below, at right), master of photomicroscopy, beamed in on a micro cosm for this month's article on the immune system. What Nilsson actually produced, with the help of his longtime friend and collaborator, Jan Lindberg, at left, was a remarkable photographic documentary il lustrating the unceasing struggle within the human body to preserve hfe. The key to his success was a powerful in strument, the scanning electron microscope (SEM), which uses electrons rather than light waves to produce images of far greater depth of field and resolution than any light microscope. Providing magnifications of from 10 to 100,000 times, the SEM enables Nilsson to pursue his life's work, which is "to show what a won derful creature is the human being"-right down to the cellular level. Clinical and foren sic pathologist for the Swedish government, Lindberg works at the Karolinska Institute in Stockholm, where he prepares the speci mens-cancer cells, viruses, damaged tis sue-for Nilsson to photograph. The in stitute, which awards the Nobel Prize in Medicine and present ed Nilsson with an honorary doctorate in 1976, provides Lind berg with a wealth of scientific resources. He obtains samples from the institute's sur gical theater and keeps them alive for days under controlled conditions. During extensive preparation, a speci- men is first coated with a fixative solution that "freezes" the sample instantly. Then it is dehydrated and coated with an ultrathin layer of gold to improve its conductivity. In a vacuum chamber at the base of the SEM, the prepared sample is bombarded with electrons, which bounce off the gold coating back to a sensor that converts electrons to electronic signals. These signals are ampli fied and sent to the SEM's screen, where they form an image. Nilsson studies such images for weeks, even years, viewing one specimen after another and waiting for the elements of a story to emerge. "Lennart never gives up," says Lindberg of his friend's legendary diligence. "He will respect no hours to get the picture he wants." Of their collaboration he adds, "Lennart is the artist." Their partnership began 20 years ago when they first teamed up for articles on fetal development and heart disease for Life magazine. Since then, they have produced a number of highly ac claimed books and films, including a 1984 Emmy winner, "The Miracle of Life."