100 YEARS AGO

We learn from the Electrician that an instrument called the telephonograph, which is a modification of the phonograph, was recently inspected and tested by the German Postmaster-General and several engineers. Its inventor, Herr Paulsen, a Dane, has replaced the wax cylinder of the Edison phonograph by a steel band, and the style by a magnet energised by a telephone. Currents transmitted by the telephone pass through the electromagnet and create consequent poles on the steel band, and more or less the converse operation is employed for reproducing the sound. A long line can, of course, intervene between the transmitting telephone and the phonograph itself, and it is suggested that a telephone subscriber on leaving his office can set such a telephonograph to receive telephoned messages during his absence.

From Nature 17 May 1900.

50 YEARS AGO

Prof. F. T. Lewis, of Harvard Medical School, has recently published an interesting comparison of the shapes of soap bubbles and of undifferentiated cells (Proc. Amer. Acad Arts and Sci., 77, No. 5, 149; 1949). He suggests that the shapes of such cells in bodies of many cells is dependent on the following five major variables.

(1) Geometrical necessity: for example, if cells are of a uniform size they will tend towards 14-hedra, though special features may reduce the facet-number below this figure. The peripheral layer of mass of 14-hedra will consist of 11-hedra, each of the 11-hedra making one surface of contact with the surrounding medium instead of four with surrounding polyhedra. (2) Surface tension and other forces tending to produce minimal surface area: with bubbles, surface tension can produce examples of unstackable combinations of twelve, fourteen, fifteen and sixteen facets which, if isolated and regular, have the least surface for volume. None of these shapes has yet been found among cells. (3) Cell division: this must involve forces opposed to surface tension, since division increases the total cell surface area. (4) Turgor: this again is opposed to surface tension. (5) Organisation: under this general heading Prof. Lewis includes all the processes whereby growth and division are “controlled to produce filaments, fibres, membranes or compact masses as may be proper for the organism”.

From Nature 20 May 1950.