Homemade Yeast

Today's recipe is not something I would ever have thought of making, and in this time of conveniece not many would really. But hey, who knows maybe one day there will be a worldwide yeast shortage and I'll have to cease buying the handy little packs put out by Fleishmans, so here it is- a recipe on how to make your own yeast. (and assuming that you have yeast cakes on hand, which must have been abundant back in 1901 or so) Put 1 yeastcake in a quart sealer 2Tablespoons sugar and lukewarm potato water at noon or after. Salt required for a baking of bread. -1 Tablespoon. 2 Mashed potatoes. Let rise till needed. Drain off the liquid leaving the sediment in the sealer for a starter (the starter was underlined, I take it that it's important) adding sugar salt each time with the potatoes and water, and one yeast cake occassionally,. So, what has this first foray into the recipes of the past teach us? People should actually explain what they are talking about! Not everyone will know what on earth you are mean,you really won't live forever to explain it to us- and we don't all have the same baking lingo-cause you know, times change- the whole imperial /metric thingy is another case in point. This recipe begins with it being a given that I'd know to boil potatoes in some quantity to have the potato water ready. Likely 100+ years ago, everyone already knew that.Me, Mom of the modern era? While, I need a bit more specifics to get me started...