Learned science journals take an off-beat approach at Christmas

In this season to be jolly, even normally serious scientists may loosen up a little, perhaps publishing frivolous research and looking on the brighter side of life.

Check the British Medical Journal at regular times of year, and you'll find sober topics like influenza A, stress and cancer and treatment of smokers. But the Christmas edition features "non-traditional" research. Last year, it included an investigation of why Rudolph's nose is red - which found that a reindeer nose has a 25 per cent higher density of blood vessels than a human nose, helping protect it from freezing during sleigh rides.

This year's issue features a review of information on the pros and cons of laughter, peppered with corny one-liners. To wit: as children undergoing minor surgery clearly did not benefit from hospital clowns, authors R.E. Ferner and J.K. Aronson suggested: "Perhaps surgical patients derive no advantage from being in stitches." (The duo should not give up their day jobs just yet.)

Benefits of laughing included lower risk of myocardial infarction (heart attacks) and higher energy expenditure, though it seems you would have to laugh long and hard to achieve significant weight loss. Laughing may even help make women conceive better, given the results of a clown entertaining would-be mothers after in-vitro fertilisation and embryo transfer.

And yet, laughter is not always the best medicine. Humour can weaken your resolve and promote brand preference, so doctors encountering those selling drugs are advised to respond: "Don't make me laugh". Some people laugh till they faint, and the report tells of a woman who died laughing, as well as noting cardiac rupture is possible - so there really are cases of laughing fit to burst. Less drastically, people have suffered sudden loss of muscle tone, though at least a woman who was only affected on the right side could presumably still laugh on the other side of her face.

A ground-breaking paper looks at that pressing medical mystery: how long do chocolates survive in hospital wards? Careful observations revealed that boxes of chocolates left in wards were opened within an average of 12 minutes and individual chocolates survived for an average of 51 minutes. Most were eaten by health care assistants and nurses, followed by doctors.

For a fact to titillate and amaze your friends during Christmas gatherings, Dutch researchers compared stem cells in a mouse and a humpback whale. Although the whale is around two million times as heavy as the mouse, they found the stem cells are similar in size.