Dear Dr. Fox: I have noticed on the ears of all the dogs we've had had a small flap near where the ear attaches to the head.

I have asked several veterinarians what this is called and what was, or is, the purpose of these earflaps. No one has been able to give me an answer. Can you help?

-- S.G., Lanham, Md.

Dear S.G.: Perhaps, like the human appendix, the tiny flaps, or vertical pockets, toward the base of the dog's ears are vestigial structures that once served some purpose.

I know of no studies of these flap-like pockets on the outer side of dogs' ears. They may contain distinctive scent glands. This we do know: They are a favorite hiding place for ticks, so it's always good to check the earflaps as well as between the toes during tick season.

Dear Dr. Fox: I'm writing to you in the hope that you will be able to help me find a treatment for my two collies. They are 2 years old, brother and sister, and they have been diagnosed with demodectic mange and are being treated with Mitaban dips.

They've been having these dips for two years. First, it was every week; then, every other week; then once a month. They seem to get better, but then it starts getting worse again.

They are now back to being dipped every other week. Our vet said there was something that would cure it, but it would kill collies.

I don't want to hurt them, so I'm hoping you know of something that might help them. They scratch all the time, and I know they are miserable.

-- C.B., Bryan, Texas

Dear C.B.: The type of mange that afflicts your dogs can be congenital in origin and develop when the pups' immune systems are impaired. Small, repeated oral doses of ivermectin can get rid of these burrowing skin mites, but the drug is, unfortunately, poisonous to collies.

So a holistic approach is called for. Check my Web site at www.doctormwfox.org for the article on Endocrine Disruption Syndrome, and use some of the dietary supplements recommended to help boost dogs' immune systems.

Dear Dr. Fox: What is your opinion of dog shows? Are they good for dogs? I have mixed feelings.

-- L.S., St. Louis, Mo.

Dear L.S.: I, too, have mixed feelings. They promote ownership and commercial breeding of pure-bred dogs by puppy mills (cruel, prison-like breeding camps).