Questions invariably arise, like, Why does this cat so enjoy sitting on plastic bags? What stimulation, invisible to my senses, does she derive from it? Is there something that could be called a simple fetish leading her to seek these sensations?

I have known other cats with similar, and more disturbing, proclivities. The aptly-named Sid Vicious was separated from his mother too early, and thereafter derived some surrogate comfort from lying in piles of dirty laundry, kneading and suckling the fabrics. He was particularly attracted to smooth and silky textures, such as women's underwear. I was a teenager at the time, and perceived the cat's behavior as a bare expression of need that terrified and disgusted me. It reminded me of the sight of animals copulating -- an expression of base impulses that shamed my notions of love and higher human purpose. As I made my first tender forays into sexuality, I desperately wanted to believe that I was more than just a creature driven to rut, to penetrate and pump the beautiful object of my early, guilty affections.

When her head is stroked, this cat is prone to roll on to its back and splay out all four paws like a wanton lover. It is indelicate to my perceptions because there is something faintly akin to human in the gesture. She is begging for gratification, which is seldom a pretty sight.

Such blatant displays of desperation and need often trigger revulsion in me, even when demonstrated by animals that don't place the same meaning on the behavior that I do. I respond to a pathetic and emotionally needy person much as I would the carrier of a virulent plague who is carelessly coughing wet blasts of spittle into my face. I am afraid that the disease that has made them so weak will infect me as well.

On the ambulance, everything changes. I respond to need. I want to use my bare hands to hold closed the rips that have opened up in patients' lives. Maybe it's one of the few places in my life where I'm not afraid of being needed, of being infected with the disease of need.

Other questions arise, such as, Why will the cat eat a certain kind of food one day and reject it the next? What subtle difference in the shape of her days crafts her changing desires? Did the warmth of Tuesday, when she sat under the table in the back yard for hours, start a biochemical process that eventually led to a craving for Turkey and Giblets on Wednesday?

The scheduled glop of Beef and Chicken, although quite the favorite yesterday, only earned me a cool stare and flip of the tail this morning. As for my palette, the unfathomable intelligence of my body is telling me that a bowl of guacamole with tortilla chips would be very tasty right now, while an ice cream cone with a scoop of mint chocolate chip on top would not.

I expect to have wants, some of which will go unsatisfied. Yet it disturbs me that the nature and texture of my needs resides somewhere out of my control. All my life, I will lug around with me a book called "hunger," written in someone else's hand and sealed to mine. Another, called "desire," a nearly indecipherable amalgam of scribbled human hand and the feverish pawings of my animal ancestors.