This is the version I learned as a kid (with "aspirin" syllabified & "flea" in ALL-CAPS to indicate how we always sang it):

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Mr. Fly climbed up a tree;
sang, "I'm as high as high can be!"
Lost his grip, came crashing down;
smashed to pieces on the ground.

When the insects heard the sound,
echoing for miles around,
they began to buzz and cry:
"Quick, first aid for Mr. Fly!"

"Get a bandage, get a splint;
"get some liniment and some lint."
"Someone give him an as-pir-in..."
"Should we call the doctor in?"

Then a wise old FLEA spoke out:
"You don't know what you're about!
"He's beyond the reach of aid;
"get a pick and get a spade."

Then the insects finally knew
what it was they had to do.
Now his tombstone bears the scrawl:
"He who climbs too high must fall."

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