50 Years Ago

It has been reliably demonstrated that rats can discriminate between the presence or absence of X-rays ... The process by which X-rays elicit arousal and orienting reactions in mammals has not yet been determined. However, for simplicity we assume this mechanism operates via a 'radiation receptor'. Attempts to locate this hypothetical radiation receptor have yielded conflicting results ... We used a narrow 3/16-in. X-ray beam as a signal or conditioned stimulus to warn the animal of a subsequent shock to the paws. The beam was most effective when it was directed at the olfactory region of the head ... In an attempt to clarify this issue, we conducted a study of the effectiveness of X-ray as an arousing stimulus in rats the olfactory bulbs of which had been removed ... The results indicate a distinct loss of sensitivity when the olfactory bulbs are removed.

From Nature 6 February 1965

100 Years Ago

In Popular Astronomy Prof. E. C. Pickering quotes some interesting letters from Profs. Backlund, of Pulkovo, and Schwarzchild, of Potsdam, with reference to astronomers and the war. None of the Pulkovo astronomers have been called to serve, but Prof. Backlund's son is in the Russian ranks, and of French astronomers, M. Croze, astrophysicist of the Paris Observatory, has been summoned, as well as the son of the director, M. Baillaud, who has six sons and sons-in-law in the war. On the German side, many young astronomers are in the field. Dr. Zurhellen and Dr. Kühl, who were with the eclipse expedition, have been interned in Russia; Dr. Münch, of Potsdam, is wounded and a prisoner in France.

From Nature 4 February 1915 Footnote 1