That first guy who unwisely used the poison ivy leaves was probably named Rosie Rear, no not Rosie Greer (grin).
The first man to notice that there were more than eight planets was Clyde Tombaugh.
That was back in 1930. Later it was found out that Pluto was just one of a whole lot of minor planets and plantetistamals. Pluto was demoted and promoted between planet and plantetistamal many times.
Now this next guy, Thomas E. Selfridge, was the first airplane fatality. Somebody had to be first, right, so this guy took that honor.
This is a photo taken of Mr. Selfridge's crash site:
It is amazing how many people were first at doing something. Well, wait a minute. I guess there always had to be someone to do something first, except there were no others before Adam, the first man. OK, now you can try to be the first person who comments on this blog (grin), and of course, have a great day, you hear?