HAVE you ever wondered which cat breeds are largest and smallest? Cats don't vary a great deal in size: There might be a feline

equivalent to the Chihuahua, but not to the Great Dane. Among the heaviest breeds are Norwegian forest cats and Maine coons, weighing 7 to 22 pounds; Siberians, 10 to 20 pounds; Turkish vans, 7 to 19 pounds; and Savannahs, 20 pounds or more. Falling into the featherweight category are the singapura, 4 to 7 pounds; and the Cornish rex, Devon rex and Japanese bobtail, all weighing 6 to 9 pounds.

* A scent-trained German shepherd mix named Frankie had an 88 percent success rate in detecting thyroid cancer in human urine samples. A study found that the accuracy of the canine "diag-nose-tician" is only slightly less than that of the more invasive fine-needle aspiration biopsy, not to mention less expensive.

"Frankie is the first dog trained to differentiate benign thyroid disease from thyroid cancer by smelling a person's urine," says study co-author Arny Ferrando, Ph.D., of the University of Arkansas for Medical Sciences, in Little Rock, where the study was conducted.