This article is from the the official alt.spleen FAQ, by Andrew Stellman with numerous contributions by others.
Andrew says: NOTE: PLEASE DO NOT SEND ANY MAIL TO ME REQUESTING MEDICAL ADVICE! I AM NOT A DOCTOR, AND WILL NOT GIVE YOU ANY USEFUL INFORMATION.
Oddly enough, yes. Researcher Daniel Martinez (email@example.com) has discovered these alarming facts:
"Apparently the widespread adoption of the stiletto as a weapon of murder in southern Italy during the late Middle Ages was an indirect consequence of the swampiness of the region. The low, wet areas were ideal breeding grounds for mosquitoes, and as a consequence Malaria was quite common there. The disease was generally accompanied by an enlargement of the spleen, which had to purify the blood of additional toxins and other by-products of infection. Any rupture of the organ, in that state, could quickly cause a victim to bleed to death. That, it seems, is exactly what the stiletto was meant to do. Long and thin, it's more suited to piercing than to slashing; supposedly the spleen of the average citizen in those parts was of sufficient size that a solid thrust anywhere in the abdominal region had a credible chance of success."