100 YEARS AGO From the hottest to the coldest stars I have found ten groups so distinct from each other chemically that they require to be dealt with separately as completely as do the Cambrian and the Silurian formations⃛. I have gone further and defined the chemical nature of these stellar genera as the biologist defines the nature of any of his organic genera: we can say, for instance, that the Achernian stars contain chiefly hydrogen, nitrogen, oxygen and carbon, and to a certain less extent they contain proto-magnesium, proto-calcium, silicium and sodium, and possibly chlorine and lithium; so that at last, by means of this recent development of spectrum analysis, we have been able really to do for the various stars what the biologist a good many years ago did for the geological strata⃛. My point is that the more one inquires into the chemistry of these things the more we come back to the stellar point of view and to the fact that, taking the simplicity of chemical form as determined by the appearance of these different chemical substances in the hottest stars⃛ and in relation to the “series” of spectra which they produce, we come to the conclusion that the first organic life was an interaction somehow or other between the undoubted earliest chemical forms.

From Nature 1 June 1899.

50 YEARS AGO The question of drug resistance will require careful investigation⃛. Experiments at Entebbe indicate that strains of trypanosomes found in re-infected animals after the first treatment with ‘Antrycide’ may have considerable resistance to further treatment. This is illustrated by an experiment in which ten cattle were dosed with 2 gm. each of ‘Antrycide’ sulphate and were then exposed to trypsanosome infection in a Glossina pallidipes area. Only one was alive six months later⃛. In some cases, animals were re-infected some months after treatment with ‘Antrycide’ and re-treated with curative doses of ‘Antrycide’ sulphate have developed cryptic but nevertheless fatal infections. Should such cryptic infections or prolonged latent infections prove to occur frequently after ‘Antrycide’ treatment, an accurate estimation of the true duration of the prophylactic effect will be difficult.

From Nature 4 June 1949.