In Ancient times, sickness was thought to be caused by an excess of blood. Therefore, doctors would cut into their patients and let some of the blood out to help cure them. This theory advanced into thinking that the human body needed all of its "humors" to be balanced: blood was one of the humors so if the doctor thought you had an imbalance, they would 'let' some of the blood out.
Cora and Mellie's hands are grasped strongly together.
Hi, you've asked an incomplete question. However, I provided a brief about DNA.
<u>Explanation:</u>
Indeed, human DNA contains a lot of information about who we are. The DNA in full as Deoxyribonucleic Acid contains genes and chromosomes which are responsible for the transfer of <em>unique</em> character traits from a parent to a child.
For example, parents who are tall <em>may </em>give birth to children who are also tall, or parents with green eyes may give birth to children with green eyes. Hence, Mrs. Robertson's assertions are to a reasonable extent in line with scientific findings.