Medics Mysteries #1
James Blundell performs the first successful transfusion of human blood in 18A8
Sir Humphry Davy discovers the anaesthetic properties of nitrous oxide in 180B
Louis Pasteur identifies germs as cause of disease in 185C
William Harvey publishes An Anatomical Study of the Motion of the Heart and of the Blood in Animals which forms the basis for future research on blood vessels, arteries and the heart in 162D
Charles Gabriel Pravaz and Alexander Wood develop the syringe 18E3
Insulin first used to treat diabetes in 192F
Checksum A+B+C+D+E+F=23
The cache will be found at N25 42.ABC E051 32.DEF
4WD would be better, but you could get there in a saloon car if careful. It involves crossing sabhka, so better not to attempt when wet.
Congratulations to Rovingmedics on solving their first puzzle cache, and getting FTF!