Toadfrog is right about the mimeograph/Ditto machine distinction. "Ditto" was a brand name; the generic term was "spirit duplicator." (Don't feel bad; many people confused the two even when they were new.)

And as I remember it, we sniffed the pages because they smelled good. I never heard of "getting high" until several years later.

Ditto machines used a paper "master." You could write or type on the master, and the thick purple ink would be deposited on the back of the paper from another sheet that was something like carbon paper. (How many people remember carbon paper?) You would tear off and discard the back sheet and attach the front sheet to the Ditto cylinder with the back side of the paper facing out, so that the print appeared backwards. As the cylinder rotated, the master would be coated with a thin clear aromatic solvent that partly dissolved the ink and allowed it to be deposited on the paper that passed through the machine. The ink that was initially present on the master was all the ink there ever was; there was no way to replace the ink when it was used up. As the ink was used up, the copies gradually got fainter until they were illegible. Then the master was useless. As I recall, you could only make about 50 copies.

Mimeographs were used when more copies were wanted. A mimeograph "stencil" was a thin sheet of waxy plastic, which you would put in a typewriter, disable the ribbon, and then pound hard on the keys (This was before electric typewriters.) so that each keystroke would cause the letter to actually cut through the stencil, making holes that ink could later flow through. But you couldn't pound TOO hard, because that would cause the enclosed parts of letters like "a" and "e" to fall out, making them appear solid black in the finished copy. The ink was thick, black, and not very aromatic. You poured it directly into the center of the drum and spread it around with a brush. As the copies got faint, you could add more ink. I never saw a mimeograph stencil wear out. I think you could use them to make 1000 copies or more.

So, if a teacher was making copies for one class, it was probably a Ditto machine. If the principal was making copies for the entire school, it was probably a mimeograph.