Life is a staircase with a number of landings where you stop climbing and just rest before continuing the journey of living.

One such landing came in 2000. After teaching in two colleges and two universities for a total of 38 years, I decided to retire and join my daughter in her move to Gainesville.

As much as I loved being a teacher, I enjoy life in retirement more because I can undertake projects that I want to pursue, not forced to do to earn a living.

Five years into retirement, I reached another platform. In 2005, I was diagnosed first with cancer, then later with Parkinson's disease. Because of the possible side effects, I decided not to have surgery or any medical treatment for cancer, but to follow a program of watchful waiting.

I joined a cancer support group that meets every month at First Presbyterian. I have nothing to contribute except for my questions. It is possible that my cancer can begin to spread and I might have to re-examine my decision not to pursue treatment. I learn much from the cancer survivors of that group.

Much about cancer is a mystery.

The same is also apparent in Parkinson's disease. For most of a year, I was told by my general physician that I did not have Parkinson's. When my trembling hand became more of a problem that affected playing my saxophone in the Believer's Band at First United Methodist Church, I went to see a specialist who diagnosed me as having Parkinson's.

I became a patient of a research physician at the Neurological Clinic of Emory University. For more than three years, I made trips through the Atlanta rush-hour traffic to see my doctor. I really hate driving in Atlanta. I now see a Gainesville neurologist, returning to Emory only once a year to participate in research.

Parkinson's disease is progressive. The part of my brain in the substantia niger does not produce enough of a chemical called dopamine. That chemical seems to be a traffic cop that coordinates all muscle activity. Those of us with PD do have tremors, which can be very small at first, like a shiver when you have a slight fever.

The longer you have PD, the shaking tends to grow. Food falls off a fork. Peas are a major challenge. Fingers refuse to work properly, as in my saxophone instance.

Some people with Parkinson's also freeze. My fingers pull back and refuse to move. Toes can also try to curl up in your shoes. PD persons sometimes develop a "PD mask" as the facial muscles tend to droop and slur speech.

Hands that shake have difficulty in hand writing, which tends to get smaller and less readable. Things drop to the floor frequently because my fingers are not grasping as they should. Tying shoe strings and buttoning buttons become more and more difficult.

It is strange to order your muscles to do something and nothing happens.

Some people with PD, as well as some with cancer, can wallow in self pity. Not me. I joined a support group at St. Paul's Methodist Church and relish the friendship and love found there.

I have participated in three research projects directed by the Michael J. Fox Foundation. In one, I joined more than 5,000 respondents in a study of all the places I had ever lived to discover if location might be a factor causing PD to develop. In another study I answered questions about possible exposure to chemicals in my environment.

Currently, I am involved in an extensive project involving a three-hour testing of my brain's ability to remember, to analyze and to recognize. This is done once a year at Emory University.

In those studies, I have learned something about my own brain. When read a list of words and asked to repeat them, I can remember about half. With numbers under 20, I can remember numbers going both forward and in reverse. This surprised me.

All my life I have liked words more than numbers. I do not know why I can remember numbers better.

One part of the project was different. A camera took pictures of my eyes as I looked at different icons on a screen.

I have donated my brain to the Emory Neurological Research Center when I die. It will be extensively studied and compared with brains from donors without PD. I thus hope to help discover some of the causes of Parkinson's, and then one day a cure.

Tom Nichols is a retired college professor who lives in Gainesville. His column appears frequently and on gainesvilletimes.com.