The Description of the Human Body He believed the heat of the heart somehow caused all movement of the body. Blood vessels he realized were pipes, he saw that veins carried digested food to the heart. (This was brought further by William Harvey. Harvey developed the idea of the circulation of the blood.) Descartes felt that an energetic part of blood went to the brain and there gave the brain a special type of air imbued with vital force that enabled the brain to experience, think and imagine. This special air then went through the nerves to the muscles enabling them to move. The Description of
To the Youth in Europe and North America to [them] through resentments and prejudices". A second open letter was written by Khamenei on 29 November 2015, following the November 2015 Paris attacks. Khamenei says that his letter, written in English, is addressed to young people who may still have open minds, not to Western leaders who, he writes, intentionally distort the truth. "I am addressing you, [the youth], not because I overlook your parents", but because "the future of your nations and countries will be in your hands; and also I find that the sense of quest for truth is more vigorous and attentive in your hearts". He