50, 100 and 150 Years Ago; October 2002; Scientific American Magazine; by Staff Editor; 1 Page(s)
HOW DIPHTHERIA KILLS-"The substance secreted by the diphtheria bacillus is one of the most potent poisons known: one milligram of it is enough to kill 31/2 tons of guinea pig. How does it work? Results from the diphtheria experiments with the Cecropia silkworm have been striking. The dormant pupa, which contains little cytochrome, will survive 70 micrograms of toxin for more than four weeks. Still more dramatic is the effect of toxin on the developing Cecropia adult. Although death may not come for days, the development of the insect is brought to a stop within a matter of hours. We assume that diphtheria toxin acts not by inhibiting any cytochrome component already formed, but by preventing the synthesis of new cytochrome."
(VERY) EARLY TELEVISION-"A Belgian engineer whose name is not known has devised a means to see electrically through long distances, just as we hear electrically by means of the telephone. At the transmitting station a rapidly rotating lens traverses, in a spiral pattern, forty times in each second, the surface of the body to which it is exposed. The lens is fitted with a screen so that only a small portion of its surface is exposed at any time. A selenium composition, the electric conductivity of which varies according to the intensity of the light to which it is exposed, is placed on the axis of rotation. At the receiving station is placed a conducting body and another lens, electrically synchronized with the first. The luminous image of the receiving body is projected in a spiral pattern on a white screen." [Editors' note: This appears to have been a working version of the electromechanical "television" patented by German scientist Paul Gottlieb Nipkow in 1884.]