The 8th lesson can be found here: http://johnkstuff.blogspot.ca/2006/06/animation-school-8-proportions-affect.html
In this lesson John talks about one thing that makes cartoons cartoony- their exaggerated proportions.
He gives an example of a generic cartoon and explains that it is less cartoony than something with unevenness built into it.
The cartoony example he gives stretches the proportions of the animal so that the shapes that are important in identifying it as what it is are caricatured and extreme.
In the more cartoony example he gives, the basic construction is similar to the less cartoony drawing but the looks of the characters are very different.
John thinks the cartoons that are more exaggerated are funnier looking.
The proportions that affect design contrast that John lists are:
When several new variations are created based off of a generic design you get particular designs. Particular designs are rare to find.