 It's a busy afternoon on the grenade practice range, throwing live grenades for the first time. Everything is going along smoothly when... Pull pin! ...something goes wrong. Prepare it! An experienced soldier is doing sentry duty. Suddenly, he's overcome by a wave of depression. At an Army training camp, Private X is on sick call for the fourth time in a week. His back hurts and he can't straighten up. But the medical officer has found nothing physically wrong with him. Overseas, a young officer is lost in some little town. He doesn't know how he got there or even what his name is. This soldier has been keeping to himself and acting strangely towards the other men. He thinks they're whispering about him. Then, in the middle of chow, he thinks the milk tastes funny and accuses his neighbor of trying to poison him. At a medical aid station, combat casualties wait to be treated. A jittery soldier, exhausted by combat experience, reacts to an unexpected noise. These men are all suffering from some form of psychiatric disturbance. There's nothing strange or mysterious about that. Nervous, emotional or mental illness can occur in anybody. The seeds are in all of us just as are the seeds of physical illness. Take any cross-section of the United States Army, a tough and rugged body of men. But not a single one of them is 100% healthy. Some have a little sinus trouble, heartache attacks and boils. Others have had repeated attacks of appendicitis, which may return in an acute form. More than half have been slightly infected with tuberculosis without even knowing it. But the scars of the old infection remain. Not one man in a hundred has a perfect set of teeth. And each man's body carries millions of germs ready to attack, should he be weakened by exposure or fatigue. Even the healthiest people aren't pure white healthy. Or the sickest people solid black sick, unless they're dead. Instead, people are somewhere in between. Neither white nor black, but some shade of gray. Most people are light gray. A lot of health mixed with a little sickness. It's the same with emotional or mental health. Slight mental or personality disturbances are present in everybody. No one is 100% perfect. Private Phillips worries too much, whether about a mortgage or a letter two days overdue. Green without cause feels that he isn't up to the standard of the rest of the outfit. Davis is quick tempered, aggressive on the surface, but really oversensitive. He can't take orders or kidding. Becker has trouble making decisions. Parker feels he's always getting the dirty end of things. His tendencies, if magnified, can seriously impair the men's ability to function. No man is without some little fear or tension, some nervousness or uncertainty. Nobody has perfect pure white mental health. Most of them are some shade of light gray, and these men are merely darker shades of gray. In them, the balance between emotional health and illness has been tipped toward the unfavorable side.