Most dogs swim and not a few take to the water at the slightest provocation. When I had a dog I used to let him swim when he felt like it. He was fond of the water, but he would never put his head beneath it to retrieve any object thrown for him. I mentioned this to a friend the other day and was told of a dog that was able to dive and swim down to a depth of something like twenty feet. The depth of the particular pool was known and the dog had been used to bring up dead salmon likely to contaminate the water. My friend told me that he was later given another dog, one by no means young. The older dog watched the salmon-retriever performing and dived into the water himself. At first he could only dive and get down two feet, but gradually he, too, acquired the ability to swim to a considerable depth. Both dogs, I was told, had a little collie blood in them, a fact to which my friend con- sidered they owed their extraordinary intelli- gence.