50, 100 and 150 Years Ago; April 2005; Scientific American Magazine; by Staff Editor; 1 Page(s)

VIRUS REPLICATION--"A new view of the nature of viruses is emerging. They used to be thought of solely as foreign intruders--strangers to the cells they invade and parasitize. But recent findings, including the discovery of host-induced modifications of viruses, emphasize more and more the similarity of viruses to hereditary units such as genes. Indeed, some viruses are being considered as bits of heredity in search of a chromosome.--Salvador E. Luria" [Editors' note: Luria shared the Nobel Prize in Physiology or Medicine in 1969 for his work on the replication and interaction of viruses.]

POLIO VACCINE--"We shall soon learn the results of last year's extensive field test of the vaccine against poliomyelitis. Whatever the analysis of that test shows, the type of vaccine that is being tested will continue to be an issue among virologists, because an immunological principle is under test as well as a vaccine. The vaccine in question is made of a 'killed' virus, that is, a virus rendered noninfectious by treatment with formaldehyde. Many virologists believe such a vaccine can never be as effective as one containing live virus. I share the view that a killed-virus vaccine not only avoids the hazards of live virus but, if properly prepared and used, may be just as effective in producing immunity.--Jonas E. Salk"