dollop of spleen

A bit of anger.

A dollop, of course, is a small lump of something--generally a colloidal food, such as sour cream or whipped cream.

"Spleen" means anger. This is no doubt related to the fact that the spleen was thought to be one of the four organs associated with the humours involving emotion--specifically it was thought to excrete black bile. whose Greek name gives us the word "melancholy".

As such, you might expect "spleen" to mean "sad", but perhaps it's better understood as "grumpy", at least when served up in dollop-sized quantities.

"If the force of gravity varies with altitude, how would that affect the height of the drop?" asked Daniel Waterhouse.

"Do it at sea-level," said Hooke, with a dollop of spleen.