50 Years Ago

It seems generally accepted that the eucaryotic cellular form ... has developed from procaryotic forms ... It often seems to be taken for granted that the transition took place in such a way that one procaryotic cell has developed into a eucaryotic one. It may, however, be just as fruitful to discuss the possibility that one eucaryotic cell has evolved from a number of procaryotic cells ... With oxygen in the atmosphere ... aerobic procaryotes must have developed. We can then assume that some of the anaerobic eucaryotes established an endocellular symbiotic relationship with aerobic procaryotes ... During further evolution, the aerobic partner must necessarily have lost a great part of its autonomy ... The final step in this evolutionary process would be the development of mitochondria as we know them from eucaryotic cells today.

From Nature 10 June 1967

100 Years Ago

Writing in 1684, Andrew Symson, minister of Kirkinner, records in his “Large Description of Galloway” that “in this parish [Glasserton] there is a hill called the Fell of Barhullion, and I have been told, but I give not much faith to it, that the sheep that feed there often have commonly yellow teeth, as if they were guilded.” In this matter the worthy minister was unduly sceptical. The Fell of Barhullion is on my property, and jaws of sheep fed thereon have been brought to me with the teeth thickly plated with iron pyrites. The rock of the district is Lower Silurian; in the softer parts (Moffat Shales) large nodules of iron pyrites are found. As there is wet peaty soil on parts of the fell there is no lack of humic acid.

From Nature 7 June 1917 Footnote 1