I agree that it looks like the boy's upper half is just out of focus, not motion blur. Motion blur shows distinct lines in the direction of motion, whereas out-of-focus is just soft. It almost looks like the plane of focus is tilted far from vertical, maybe at 45 degrees or so. If the plane of focus was vertical, you couldn't get things both in front of and behind the kid, and his feet, in focus. The foreground, and a fair bit of the background is in focus but it goes out of focus farther from the ground. You can do that with a view camera, but it's hard to do it to this extreme by accident. So it must have been intentional - but why? The depth of field appears tiny, too.

A 1908 glass negative where the exposure is so long the child is blurred from movement.... yet the dog and cat sat still long enough to be in good focus? I think the animals are stuffed props of the studio (along with the wagon, background and clothing).

[The dog's head shows slight motion blur. It and the cat, both live animals, are also seen here. The boy's head exhibits optical, not motion blur. -tterrace]

To be forced to sit in a small wagon with an 80 lb. dog who happens to have jaws like an alligator.

(Woof!) That's my dog Tige, he lives in a shoe. I'm Buster Brown, look for me in there too.

The ones your parents drag out and embarrass you with 20 years later.