The history of blood letting

09 June 2015

Interview with

Richard Barnett, Science Historian

Before blood transfusion got going, and the important role of the blood systemBlood test was appreciated, doctors were more fond of taking the stuff out of people - and they had some pretty ingenious implements for doing so. Heather Douglas went to the Wellcome Collection in London to take a look at some, alongside science and medicine historian, Richard Barnett...

Richard - We're here in front of three objects which point towards the most widely used medical therapies in history, which is bleeding. This is a medicine which is based on the idea of balance and the balance of four humours.

Heather - The idea of humours dates right back to the ancient Greeks. The theory goes that the body has these four disgusting-sounding liquids: black bile, yellow bile, phlegm, and, of course, blood. To keep healthy, they had to in balance...

Richard - Within this system, blood has a particular function. Blood is the nutritive humour. The idea is that blood is made in the liver and then sent out around the body and it carries food essentially and disease in this model is imbalance. You can have too much of a humour or too little of a humour. If you have too much of a humour, the doctor's job is to get rid of it and this is where bloodletting comes in.

Heather - Bloodletting wasn't the only way to balance the body, but it was an easy and popular treatment because everybody bleeds. It was so popular, that implements called scarificators were specially designed to get blood flowing. We took a look at some particularly gory ones.

Heather - There's one that's a metal box with blades sticking out.

Richard - Yeah, it's basically spring loaded - it's a bit like a pistol. You'd sort pull back a hammer, press it against the skin and press a trigger and steel blades would come shooting out of the skin.

Heather - That sounds horrible.

Richard - The other one is a razor crossed with a lawnmower and you sort of begin, run it along the skin and it would open up the skin and allow you to bleed.

Heather - It all sounds quite horrible to me. What diseases would they prescribe bloodletting for?

Richard - Pretty much anything. You would prescribe it for diseases where there was an excess of blood. If you have too much blood in your body, you get overheated, feverish, you get over excited. So, letting out blood was a way to sort of calm somebody down. Of course, if you lose 3 or 4 pints of blood, physiologically, you get calmer, to the point of unconsciousness.

Heather - How did we come away from this idea of blood coming from the liver and begin understanding blood?

Richard - It's not until the end of the 18th century that ideas about therapeutic bloodletting really start to change and that's with the revolution of medicine called Paris medicine. Doctors start thinking more surgical, they start thinking about fine little structure and the detailed anatomy of the human body. They start also to collect data on patients. One of the things that becomes very clear from this data is that therapeutic bloodletting has no effect whatsoever. This is where you start to get the idea of transfusion.

Heather - If you needed blood that stick needle in my arm with a tube and stick the needle in your arm and hope it flowed the right way?

Richard - Well, exactly. You have to be able to connect the pipes the right way around. But yes absolutely, a very simple and a very effective way especially on battlefields.

Heather - But they didn't start directly with human-to-human transfusions, did they?

Richard - Well, there was a long history of experimental transfusion looking back to the old classical idea of your humours determining your character. So, the idea was if you took blood out of a kind of angry vicious dog and put it into a sheep and vice versa, you might get an angry vicious sheep and a rather calmer, sheep-like dog.

Heather - Did they apply that to people as well?

Richard - There were some experiments with transfusing blood into criminals to try and sort of calm criminals. But the problem that all of these early transfusions faced was that very, very rarely, they'd work. There was really no sense of why this was happening until Karl Landsteiner who elucidates the blood groups.

Heather - So, he was the one who discovered blood types.

Richard - Yes. His work is part of a movement to try and understand the immune system and then the other functions of blood as well.

Heather - Once blood groups were discovered, it was recommended that people were tested before transfusion, which still happens today. But to start with, there was a problem of actually storing blood.

Richard - This becomes a real problem a few years after Landsteiner's work with the outbreak of the First World War. Suddenly, blood loss becomes a problem of selecting all of the blood European armies. It's discovered during the First World War, I think quite by chance, that mixing some sodium citrate into the blood stops it from clotting. So, you can start to store blood, you could start to build up blood banks. In 1939, at the outbreak of the Second World War here in Britain, you get blood banks set up in London and the blood transfusion service proves its worth during the blitz.

Heather - That was the real start of donation and people at home would go along then give their blood.

Richard - Yes. This is where scientific developments starts to mesh with cultural ideas. Here in Britain, ever since the '30s and the '40s, we've had this idea that blood transfusions are kind of civic duty. It's something you can do for society with the idea that if and when you need it, somebody else will be there to do it for you.

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