The late-model Perfecscope is mostly made out of aluminum. By 1900 aluminum had become relatively cheap, and a viable alternative for the wood and leather these things would previously have been made of. Another more-modern trait of this stereoscope or stereoviewer is that the hood and lens-holder parts are also glued together.
That gluing makes this about as far as it can be taken apart for cleaning, without resorting to more drastic measures (e.g. boiling water). The handle-bracket had been bent out-of-shape, but fortunately could be bent back without breaking.