The ‘supervisor’ keeps a PhD candidate on the straight and narrow. A thesis, however, must be entirely the student’s own. That wasn’t always the case. In 18th-century Sweden, for example, the text was written, or dictated, by the supervisor. The candidate’s job was merely to defend the results publicly.
The arrangement must have suited the great Carl Linné, better known today as Carolus Linnaeus, the Latinised version of his name. He presided at the conferring of 186 PhDs — many of them he had written himself. The ‘Prince of Botanists’ didn’t lack self-esteem. It is even said that he published a review of his autobiography under an assumed name. No doubt, he ‘always knew best’.
In 1749, he supervised the work of 20-year-old Nils Hesselgren, whose subject was the dietary preferences of farm animals. The data collected 275 years ago for the thesis is still held in the archives of Uppsala University. Researchers have now made it available ’with modern nomenclature’.
Strict scientific protocols govern such studies nowadays, with all ‘ifs, buts, and caveats’ addressed and conclusions justified statistically. In reading the resurrected thesis, however, allowance must be made for the more ‘anecdotal’ approach to research in Linnaeus’ day. Statistical analysis would not become ‘de rigueur’ for another 200 years. Also, research, back then, was utilitarian… projects were expected to yield practical results.
Visiting Dalarna, a province in central Sweden, Linnaeus noticed that although horses ate a wide range of herbs, they scrupulously avoided certain species. Was this true of all livestock, he wondered? If so, it might have practical implications for farming and so was worth investigating. The task fell to Hesselgren.
More than 2,300 tests were carried out in which 643 species of plant were offered to cattle, sheep, horses, goats, and pigs. Which herbs would each species shun?
Pigs proved to be the most pernickety diners; they ate only 32% of the species offered. This was no surprise. Unlike the other participants in the experiment, pigs are not strict vegetarians. Eating both plant and animal material, they can afford to turn their noses up when more tempting morsels are available.
Horses were also quite choosy eaters. They dined on 59% of the 204 species presented to them. Cows ate 66%, and sheep 82%. Goats were the most profligate, eating 84% of offerings.
Oddly for such intelligent animals, pigs were not good at identifying toxic species. Cows and horses were the most discerning in this respect.
On publication, the thesis was widely circulated and translated into German and English.
But what do reviewers make of it today?
They find the work to be surprisingly modern. “Methods are well described,” they say, and the “raw data are available, a practice that has been the rule in scientific publications only in the last decade”. The main criticism is that those data were not really analysed at all. “This may well have been the first ecological experiment in the world, but more important is the stunning scale of the operation.”
