100 YEARS AGO

“The Dynamical Theory of Gases.” In Mr. Jean's valuable work on this subject he attacks the celebrated difficulty of reconciling the “law of equipartition of energy” with what is known respecting the specific heats of gases. Considering a gas the molecules of which radiate into empty space, he shows that in an approximately steady state the energy of vibrational modes may bear a negligible ratio to that of translational and rotational modes. I have myself speculated in this direction; but it seems that the difficulty revives when we consider a gas, not radiating into empty space, but bounded by a perfectly reflecting enclosure. There is then nothing of the nature of dissipation; and, indeed, the only effect of the appeal to the aether is to bring in an infinitude of new modes of vibration, each of which, according to the law, should have its full share of the total energy. I cannot give the reference, but I believe that this view of the matter was somewhere expressed, or hinted, by Maxwell. We know that the energy of aetherial vibrations, corresponding to a given volume and temperature, is not infinite or even proportional to the temperature. For some reason the higher modes fail to assert themselves.

Rayleigh

From Nature 13 April 1905.

50 YEARS AGO

Sir Alexander Fleming, the discoverer of penicillin, died suddenly on March 11 at his home in London... The First World War directed his attention to wound infection and its control; he was one of the first to show that most wounds become infected after admission to hospital... In 1922 came the discovery of lysozyme. Following an observation that his own nasal secretion after a common cold had an inhibitory action on some of the bacteria present in the nose, he showed that this lytic substance was present in many tissues and secretions of the body... His work with lysozyme prepared the way for the epoch-making discovery of penicillin. Fleming had been studying variation in the staphylococcus, which meant that he was frequently examining colonies of that organism as they appeared on ordinary nutrient agar. As a result of this exposure, a mould appeared on the culture medium some days later and Fleming noticed the unusual phenomenon of the disappearance of staphylococcal colonies around the mould.

From Nature 16 April 1955.