His new guardians were Tim Hansen, a computer lab aide at Ogden Elementary, and his wife Paula.

"They said this was his last chance," Hansen said, glancing fondly at the glossy-coated dog. "He looked pretty ratty then, but he cleaned up well."

After initially talking it over with school principal Jim Armendariz, Hansen has been bringing Mac to work every day.

"Mac got on-the-job training," Hansen said.

There is no state law requiring certification of dogs brought into Kansas schools.

According to Hansen, Mac is very dedicated to his work at the school.

"I tell him it's time to go to school and he is up and ready to go," he said. "On days we don't go to school he looks as me as if to ask, 'Now what am I going to do?'"

Hansen said Mac — who sticks pretty close to his master — is in charge of his own schedule.

"He greets the kids as they come in," he said, adding that the good-natured dog "goes out at recess and lets (the students) chase after him."

At other times, Hansen said students who struggle with reading aloud will come into the computer lab and read to Mac.

"A lot of first-graders don't like to read to people," he said of their tendency to stumble over words. "But they know Mac doesn't care."

Students who need to take time out of a class because of behavioral issues or emotional stress also can visit Mac on an as-needed basis. Hansen said the students often take Mac for a walk around the building.

"They divert their attention from the problem to the animal," he said.

Armendariz said Mac's presence has been a "blessing for many children."

"We'll try anything we think will help the children," Armendariz said. "If it doesn't work, we quit. If it does work, we keep doing it.

"We had children here that wouldn't work until Mac, and children that took responsibility because of Mac," he added.

Armendariz said having Mac along with other classroom pets — including a snake and a rat — teaches students to value other lives.

"We teach the children to treat animals well because we believe they will transfer that behavior to life in general," he said.

Armendariz said sixth-grade student — and longtime friend of Mac — Tyler Devin has made significant improvements in his academic performance.

Some of that, he said, can be attributed to the time he spends with Mac.

"It's a mutual friendship," Armendariz said. "Mac has been good for him, but Tyler helps walk and feed Mac."

Devin, an 11-year-old who scored a perfect 100 on last year's state math assessment, said Mac cheers him up when he is upset.

"I just pet him and throw his ball down the hall." he said of the routine he keeps.

"He is a man's best friend," Devin quipped.

Mac is one of three therapy dogs in the Manhattan-Ogden School district. He is joined by Riley at Woodrow Wilson and Bailey at Manhattan High School West.

According to the Reading Education Assistance Dogs Web site, www.therapyanimals.org, research has shown that when children get nervous, especially when talking to others, their blood pressure can rise, but if a dog joins the scene, their blood pressure will fall.

Other research has also shown children who spent time with dogs expereicne increased relaxation and a tendency to forget about pain and limitations.

Armendariz, who comes from a "veterinary family" that trains guide dogs, said he was confident about the research findings.

"Pets are calming," he said. "I've seen many of the benefits."