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Blood is approximately twice as thick as water because of the cells and other components found in it.
Patients who have undergone chemotherapy for the treatment of cancer often complain of a lack of mental focus; memory loss; and a general diminution in abilities such as multitasking, attention span, and general mental agility.
Long-term mental and physical effects from substance abuse include: paranoia, psychosis, immune deficiencies, and organ damage.
It is believed that the Incas used anesthesia. Evidence supports the theory that shamans chewed cocoa leaves and drilled holes into the heads of patients (letting evil spirits escape), spitting into the wounds they made. The mixture of cocaine, saliva, and resin numbed the site enough to allow hours of drilling.
About 100 new prescription or over-the-counter drugs come into the U.S. market every year.
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