William Harvey, by means of dissection and observation, concludes that much of what we know about the heart is the opposite of how it actually functions.
The heart has two positions, stiff and soft. It stiffens when it contracts, and softens when it rises and presses against the breast. At that point the pulse is felt externally.
When the heart contracts, it is pushing out blood. If one were too feel the heart during the process, one would feel it harden. This action is similar to what the muscles of the body do. The hardness is the product of tension.
When the heart contracts and pushes out the blood, it can be seen to grow paler in color, and then brighten again when more blood rushes in.
It was previously believed that the heart was pushing out blood when one felt the pulse on one’s chest, but on the contrary that is when the heart is filling up with blood and preparing to push it out when it contracts.
Timothy Bulso
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