Aristocratic Families
The British first referred to the royal family and titled nobility as ‘blue bloods’ in the early 1800s. The Dukes, Marquesses, Earls, Viscounts, Barons and especially their women prized fair skin, because it was a sign of being upper class. The fair skin of a noble Lord or Lady displayed blue veins. This may have been where the idea of “blue bloods” came from.
The Spanish nobility boasted of being blue bloods as early as the 9th century. Of course, even then, people knew the truth. An injured or slain nobleman always bled red.
How Blood Works
Our blood carries a protein named hemoglobin, which contains four iron atoms. When oxygen binds to the iron, the blood turns bright red. Fish, birds, reptiles, amphibians, and mammals all have red blood cells.
Those who have red blood are also vertebrates, with backbones.
Our blood vessels transport oxygen to our tissues and carbon dioxide back to the lungs, where it is exhaled. Even fish capture oxygen and expel carbon dioxide through their gills.
Alligators are unusual because they have an exceptionally powerful immune system. This is important for a swamp dweller. Louisiana scientists discovered alligator blood serum killed sixteen strains of bacteria. In contrast, human blood serum killed only six.
But there is a handful of creatures living on earth who have blue blood.
The True Blue Bloods
Blue blood uses copper atoms, instead of iron to transport oxygen and CO2 molecules. The protein is called hemocyanin, instead of hemoglobin. Most blue bloods are sea creatures. The octopus has blue blood. So do lobsters, crabs, squids, scallops, snails, barnacles, mussels, shrimp, crayfish, clams, and 
most spiders.
So why don’t we notice these sea creatures bleed blue?
Well, for one thing, a crab’s blood supply doesn’t travel via a network of blood vessels. Instead it bathes the tissues, along with other fluids. So crab’s blood is diluted and appears as a light bluish gray. Of course, spiders, scallops and barnacles have very little blood.
But one ocean creature is different. The horseshoe crab’s blood is bright blue. This ancient living fossil has a blood protein which can detect bacterial contamination. The medical industry depends on this protein so much, a pint of horseshoe crab blood is worth $15,000 or more.
Why am I writing about blood this week? Because decades ago, I received a heavenly transfusion which changed everything.
The Spiritual Point
No matter what the color, blood takes away waste and brings life-giving oxygen to all our cells and tissues. But we have to keep breathing. Oxygenated water must continue to flow over the fish’s gills and air into the alligator’s lungs. Blood needs to keep circulating too. When it stops, physical death occurs within a few minutes.
Jesus Christ’s blood offers a permanent cure. When we accept Christ as our Savior and Lord, His blood forever cleanses us of our defiling sins. At the same instant, His blood also gifts us with eternal life.
Divinely powerful blood indeed.
These images came from Pixabay.com.
Resources:
Images showing the blue blood of horseshoe crabs.
Here’s why horseshoe crab blood is so valuable . (59 second video)
10 Incredible Horseshoe Crab Facts from the Smithsonian’s National Zoo.
