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Autoimmune diseases occur when the immune system destroys its own healthy tissues. When this occurs, white blood cells cannot distinguish between pathogens and normal cells.
According to the Migraine Research Foundation, migraines are the third most prevalent illness in the world. Women are most affected (18%), followed by children of both sexes (10%), and men (6%).
Ether was used widely for surgeries but became less popular because of its flammability and its tendency to cause vomiting. In England, it was quickly replaced by chloroform, but this agent caused many deaths and lost popularity.
Adult head lice are gray, about ? inch long, and often have a tiny dot on their backs. A female can lay between 50 and 150 eggs within the several weeks that she is alive. They feed on human blood.
Multiple sclerosis is a condition wherein the body's nervous system is weakened by an autoimmune reaction that attacks the myelin sheaths of neurons.