|
|
Hippocrates noted that blood separates into four differently colored liquids when removed from the body and examined: a pure red liquid mixed with white liquid material with a yellow-colored froth at the top and a black substance that settles underneath; he named these the four humors (for blood, phlegm, yellow bile, and black bile).
Most childhood vaccines are 90–99% effective in preventing disease. Side effects are rarely serious.
Children of people with alcoholism are more inclined to drink alcohol or use hard drugs. In fact, they are 400 times more likely to use hard drugs than those who do not have a family history of alcohol addiction.
Sildenafil (Viagra®) has two actions that may be of consequence in patients with heart disease. It can lower the blood pressure, and it can interact with nitrates. It should never be used in patients who are taking nitrates.
Normal urine is sterile. It contains fluids, salts, and waste products. It is free of bacteria, viruses, and fungi.
![Sickle cell anemia. The clinical manifestations of sickle cell anemia result from pathologic changes](https://biology-forums.com/gallery/47/medium_14755_01_10_12_7_58_57_9218989.jpeg)
![This pre-Anasazi community in Mesa Verde, Colorado, was carved into a cliff, making it nearly impreg](https://biology-forums.com/gallery/47/medium_6_15_08_15_11_36_37_22212666.jpeg)