My lip is bleeding again.

When you teach tennis, it doesn't surprise you when suddenly you taste blood. The skin sears quietly under the sun and floats in dissolving sheets off the lip. Sometimes you can feel it split and begin to burn with a mixture of sunscreen, sweat and blood. Other times, you can't feel anything because, like a boxer who has been hit in the same place so many times, you go a bit numb. Invariably you'll be teaching a lesson, delivering a mini-lecture concerning a specific rudimentary element of the game, when the skin parts and the blood comes, soft and wet over the crooked surface of your lip, and you'll notice that your student is staring at your mouth. But by then there's nothing you can do but press the back of your wrist to your lip and hope it stops, because it's hard to get a student to focus when his coach is bleeding.

Most of the year I teach with no problems in this area, but when summer starts, it's just the way it goes. I swallow quickly then press my lip into the sleeve of my shirt, which I remember isn't a good idea when I see a broken thumbprint appear on the fabric below my shoulder. The thermometer above the tennis court says 104. It's not even noon. I've got lessons stacked up for the rest of the day. It's been a long summer.

My early morning lessons just drained me of all my energy, and I'm weary and fatigued. Sometimes a trail of physically and emotionally demanding students can sap all your energy, and so far today, that's all I've had.

My first lesson was with Steve Troype, a big, angry guy who wants me to feed him basket after basket of forehands only, which he rips as hard as he can at me. Troype is a pretty lousy player, but he's athletic and skilled enough to make solid, but unpredictable contact that sends the ball at odd, bursting angles that, because of their velocity, are almost impossible to anticipate. Because it's hard to track his shots, during every lesson with him I get hit several times in the back, arms, legs and shoulders. "I'll knock that hat off your head one of these days," he said today with rueful sincerity.

After Troype, 10-year-old Benny Fineman arrived with his enormous Prince bag that contained only one racket, but about 10 Universe Space Scuffle books.
"Have you read the Universe Space Scuffle books?" he asked.

"No, I've never even heard of them," I said.

"Do you remember when Captain Broot found the colony of Ozeros fighters?"

"No," I said, "I've never read the books before."

"What about when Snepros decided not to go back to the planet Uteloeou and was named admiral of the Myablo fleet?"

"I don't know anything about that," I said, "because I've never read any of those books."

"Did you think that Agent Sandy was going to shoot Stivar, the computer expert, when he found out that she sneaked on the ship?"

I could see it wasn't going to end.

"I did."

"Me too," he said excitedly. "I almost had to stop reading because I was so nervous that she was going to kill him."

"But she didn't?"

"No, she didn't, but that would have been awful, don't you think?"

"I do."

After we picked up the balls, I had a 10-minute break, so I waited there on the court for my next student to arrive.

The gate opens and an older man in his sixties comes onto the court. He's carrying an old racket bag and walking slowly toward me. He's thin and bald, and on each side of his head are two patches of silver hair. They look like the stumps of wings. He takes off his sunglasses and smiles at me.

"Dr. Bloom," he says, extending a hand.

When our hands meet, I can feel something in his palm that I've never felt before. His hand shakes, slightly at first, then more noticeably as the handshake continues.

"I might be a difficult student for you," he says.

"Why's that?" I ask.

"Have you ever taught anyone with Parkinson's disease?"

"No, I haven't."

"Well, you're about to," he says.

Dr. Bloom goes on to tell me that he played tennis for 30 years at the Mill Valley Tennis Club and was once rated as high as a 4.0, but when the tremors in his hand were diagnosed, he never played tennis again. That was 10 years ago.

"I had a dream last week," Dr. Bloom says, "that I could still hit a ball and when I woke up not only did I believe it was true, all I wanted to do was come here and hit that ball. But I have to warn you, even without Parkinson's, my strokes were a bit unorthodox."

Dr. Bloom swings his racket through the air a few times. "I've noticed," he says, "that when I do things quickly, like swinging a racket, for example, the tremors lessen considerably, kind of like how people who stutter can sing beautifully without even the slightest trace of a stammer. I just want to hit balls again and feel that easy fluidity that happens when you hit it right."

Dr. Bloom goes back to the baseline, and I slowly feed him balls to his forehand and backhand. Both sides are obviously rusty, but he's right; in his stroke there is no evidence of a tremor at all. After a few minutes, he still hasn't hit one ball over the net yet and I realize that his biggest problem is that he takes a huge backswing with the racket literally up in the air, so when he finally gets around to hitting the ball, he's way too late. I explain to him that he should begin his swing with the racket head low and finish with it high, rather than the other way around.

"I see what you mean," Dr. Bloom says, taking a few practice swings. "That makes perfect sense."

I go back to my basket and begin feeding him balls again. He hits the first one cleanly and beautifully across the net, and it lands deep toward the baseline.
"A-ha!" he exclaims, "I've been wanting that feeling for years!"

His backswing is short now, and he finishes out toward the court with a direct and smooth follow-through. For the rest of the basket, he uses his new stroke and not only do most of the balls land in, they land in relatively the same area.

"This is marvelous, just marvelous," he says.

By the second basket, his bad habits come and go from shot to shot; he's a little wristy at times, and he tends, on occasion, to hit with the wrong foot out in front, but he can get the ball back now, and that's what counts the most. I'm about to suggest checking out his serve, when suddenly Dr. Bloom approaches the net and shakes my hand.

"Well, I knew you could help me," he says, "and you did. Thank you."

"But Dr. Bloom, we have more to do," I say.

"I knew I could hit a ball again and you proved that I was right. I did exactly what I wanted to do today, and it's all thanks to you. Nothing could make me as pleased as I am now about my game."

"But there's more time," I say, looking at my watch. "You've paid for an hour, and it's only been 25 minutes."

"I took a certain amount of your time," he says, shakily putting his racket back in his bag, "and I'd like to give the rest of it back to you."

He shakes my hand again.

"Thank you and good day."

When he leaves, I stay standing at my basket, unsure of what to do next. Behind my court, a small boy with thick brown glasses is crouching on the ground in the bushes, a shoe box by his side. I recognize him as Jacob Reese, who is one of the best eight-year-olds in the club. Jacob has really learned how to hit a good ball, but his progress is inevitable considering his lifestyle. In the summer, his parents drop him off at eight in the morning and pick him up at five. They give him a cooler with food and a few dollars for candy, and they enroll him in endless tennis and swim lessons; he's supposed to fill the gaps of time in between the purchased activities with whatever one fills summer days at country clubs with when they have no other choice.

"What's in the box?" I ask.

"You have to whisper," he says, looking up at me.

"What's in the box?" I whisper.

"Lizards."

Sure enough, in the box, which is lined with paper towels, are about eight lizards.

"Did you catch them?"

"I caught all of them, and now I'm releasing them."

He takes one out with a great deal of care, and with an impressive amount of finesse, he whispers something close to its head and puts it on the ground. The lizard digests its newfound freedom by pausing to make sure it's on the level and not some trick, then darts into the darkness of the bushes.

"That was Flappy."

"You name them?"

"Yes," he says. "Every day I catch 10 lizards. I play with them and then I release them. I've already let three go, but do you want me to tell you the others' names?"

"Yeah."

He points in the box: "Dizzy, Slippy, Foffo, Bloopy, Hippy, Skater and Magnus."

"Magnus?"

"He's Swedish."

Jacob takes out another lizard, whispers something and watches it run away.

"What do you say to them?"

"Well, I say their name and then I say goodbye. I just released Flappy, so I said, 'Goodbye, Flappy,' and then I let him go."

Jacob lets another one go and then he turns to me with his big frames with lenses that make his eyes look enormous.

"Do you want to say goodbye to one?"

"I do."

"This is Skater," he says, handing me the lizard. Its body is small and pulses quietly in my hand.

"Goodbye, Skater," I say quietly, putting the lizard on the ground. No sooner have I whispered his temporary name than he vanishes into the brush. Jacob lets me help him do the rest, and they all go in different directions, but they all vanish the same way; a little at first, so you can see a tail sticking out from below a leaf, and then it's as if they were never there at all.

I'm almost 30. It's getting hotter out here by the minute. It's the happiest I've been all summer.

Alex Green teaches English at St. Mary's College in Moraga, Calif.