>> rosenbaum: today's date? >> uh-huh. >> rosenbaum: today's date? at this point? >> kawas: yes. ted has dementia. >> stahl: he does. >> kawas: you know, unfortunately there's no blood test, there's no x-ray. it's an examiner finding out that an individual has problems in two or more of the main things the brain does for them. so that's where he is. >> stahl: and what's perhaps the most devastating is he knows it. >> rosenbaum: my worst condition is my memory. >> stahl: when you can't remember something, what goes on inside you? >> rosenbaum: terrible frustration and terrible... you know, it's... it's having more and more of a negative impact on me, psychologically. >> stahl: determining what's behind his memory loss isn't easy, since diseases like alzheimer's can only be definitively diagnosed in the brain after death. so it's after the 90-plusers die that a new round of sleuthing begins. when subjects in the study donate their brains, they come here to neuropathologist dr. ronald kim. he showed us one of the things he always looks for, the plaques

. >> this is a little animated video put together by a guy named adam rosenbaum.ner is -- ♪ ooh, he meets a lady. what's up, girl? sup? >> now he's got the dig. >> he got the digits. 555 555-2-drunk. it looks like it happened in december of 2007. >> when tickets to the theater were still 9 bucks. >> still in the single digits. they're going to a bulls game, hanging out in chicago, in front of the chicago bean, no less. do they call it the bean? >> it's called the -- >> i always call it the bean. whatever. that go i recall irl is amanda. adam, the brilliant artist, created this video because he had something he wanted to say. you mean the world to me. and then we see an animated diamond ring. what could this be? >> a proposal! >> that's exactly what it is. we see a lot of proposal videos on the web. people down on one knee proposing in garden, in boats, on innertubes. how many animated videos have we soon? >> love it. he could probably sell this video, get somebody else who wants to do a proposal, get a template and plug in your own thing. instead of a cat, i'd lik

the second question, did that have crossed the paths of the rosenbaums. >> the folgers were married in elizabeth, new jersey and their early years they lived with emily's parents in elizabeth, new jersey and there were already standard oil refineries in that area. some of the know, having driven through there. they moved to brooklyn in the 1880s and in 1895 they relocated to a larger house. it was in the bedford area of brooklyn. what was your second question? rosen balk is a figure who appears in chapter 6 because he was the main provider of books for huntington and folger. he was a master bookseller and dancer, dancing back and forth between these two book collectors keeping them both happy and he might say for instance, mr. folger, are you interested in this third quarter of? i will be going to california next week, so there is a marvelous biography of rosenbalk by fleming which is available in the museum in philadelphia which i recommend to all of you. >> simple question, in your research did you come up with an answer to the question why washington? this in the 1910s, 20s, 30s, th