Darkness approached and a cold, angry wind gnawed at the tent like a mad dog. Camped above treeline in the Wind River Mountains of Wyoming, the torrents of air were not unexpected and only a minor disturbance compared to the bestial gnawing going on behind my belly button. In an attempt to limit exposure of my bare bottom to the ice-toothed storm, I had pre-dug a half dozen catholes within dashing distance. Over and over, through the long night, the same scenario was repeated: out of the bag, out of the tent, rush, squat, rush back. 'Everyone can master a grief,' wrote Shakespeare, 'but he that has it.' Diarrhea, the modern word, resembles the old Greek expression for 'a flowing through.' Ancient Egyptian doctors left descriptions of the suffering of Pharaohs scratched on papyrus even before Hippocrates, the old Greek, gave it a name few people can spell correctly. An equal opportunity affliction, diarrhea has laid low kings and common men, women, and children for at least as long as historians have recorded such fascinating trivia. It wiped out, almost, more soldiers in America's Civil War than guns and swords. In the developing world today, acute diarrhea strikes more than one billion humans every year, and leaves more than five million dead, usually the very young. Diarrhea remains one of the two most common medical complaints of humanity. 'Frequent passage of unformed watery bowel movements,' as described by Taber's Cyclopedic Medical Dictionary, diarrhea falls into two broad types: invasive and non-invasive. From bacterial sources, invasive diarrhea, sometimes called 'dysentery,' attacks the lower intestinal wall causing inflammation, abscesses, and ulcers that may lead to mucus and blood (often 'black blood' from the action of digestive juices) in the stools, high fever, 'stomach' cramps from the depths of hell, and significant amounts of body fluid rushing from the patient's nether region. Serious debilitation, even death, can occur from the resulting dehydration and from the spread of the bacteria to other parts of the body. Non-invasive diarrhea grows from colonies of microscopic evil-doers that set up housekeeping on, but do not invade, intestinal walls. Toxins released by the colonies cause cramps, nausea, vomiting, and massive gushes of fluid from the patient's lower intestinal tract. Non-invasive diarrhea carries a high risk for dehydration. In Paragraph 1, the author uses the quoted word 'grief' from Shakespeare to refer to ______.