How many eggs to coagulate one quart of milk?

You don't coagulate milk with eggs. You use rennet, a natural enzyme found in the stomachs of calves, or a commercial rennet substitute to curdle milk and separate the curds from the whey.

Eggs are used in custards, sauces, and puddings where they act as a thickener, but they don't coagulate milk.

If you're trying to make cheese, you'll need to use rennet. Let me know if you'd like to learn more about cheese-making!