Now in our 13th year of bringing you beautiful imagery from biomedical science every day

Search the archive of over 4000 images

Born on this Day Visionary of Colour
30 October 2014

Visionary of Colour

Ragnar Granit, a Finnish-Swedish physiologist, was born on this day in Helsinki in 1900. He received the Nobel Prize in Physiology or Medicine, along with George Wald and Haldan Hartline, for his discoveries concerning colour vision and other processes in the eye. By attaching microelectrodes to individual cells in the retina – a light-sensitive nerve net lining the inner surface of the eye – he demonstrated that light not only simulates, but also inhibits, impulses shooting along the optic nerve to the brain. He also showed that to have colour vision, some eye receptor cells are sensitive to the whole spectrum, and so are not colour specific, while others respond to a much narrower band, only reacting to particular colours. Here’s a scanning electron micrograph of the fovea, the area in the retina that contains only receptor cells and produces the sharpest image in the brain.

Written by Nick Kennedy

Search The Archive

Submit An Image

Follow on Tumblr

Follow on Instagram

What is BPoD?

BPoD stands for Biomedical Picture of the Day. Managed by the MRC Laboratory of Medical Sciences until Jul 2023, it is now run independently by a dedicated team of scientists and writers. The website aims to engage everyone, young and old, in the wonders of biology, and its influence on medicine. The ever-growing archive of more than 4000 research images documents over a decade of progress. Explore the collection and see what you discover. Images are kindly provided for inclusion on this website through the generosity of scientists across the globe.

Read More

BPoD is also available in Catalan at www.bpod.cat with translations by the University of Valencia.