Scottish blood?

A wealthy Arab Sheikh was admitted to hospital for heart surgery, but prior to the surgery, the doctors needed to store his type of blood, in case the need arose. As the gentleman had a rare type of blood, it couldn't be found locally, so, the call went out.
Finally a Scotsman was located who had a similar blood type. The Scot willingly donated his blood for the Arab. After successful surgery, the Arab sent the Scotsman in appreciation for giving His blood, a new BMW, a 5-carat diamond and $50,000 dollars.
A few months later, once again, the Arab had to go through a corrective surgery. So the hospital telephoned the Scotsman who was more than happy to donate more of his blood again.
After the second surgery, the Arab sent the Scotsman a thank-you card and a box of chocolates. Needless to say, the Scotsman was shocked that the Arab did not reciprocate his kind gesture as he had before. He phoned the Arab and asked him: "I thought you would be generous again, that you would give me another BMW, diamonds and money ... but you only gave me a thank-you card and a box of chocolates."
To this the Arab replied: "Aye laddie, but I now have Scottish blood in ma veins".