Your first link doesn't work and Wikipedia has stated that it was removed because people were adding erroneous information. As for the second, what on earth does testing of a consolidant for soluability in alcohol have to do with anything? Sorry, but the rest of your post is almost entirely wrong.
Consolidants are used to make contact lenses comfortable and as stated in the URL to restore leather book binding; and from what I read, not necessarily the parts that bend as it acts as a polymer filler (see my second URL).
Consolidants are
not used as fillers, unless they are being very badly
misused. That is why they are dissolved in alcohol in the first place: so they can
penetrate the leather. Anything left on the surface is wiped off. You don't want
any on the surface. That is what
sealer is for. Consolidants
consolidate the leather, which is why they are
called consolidants. The word consolidate means to gather and hold together.
To state that the leather covering of a book doesn't bend is just ridiculous. You do have to open a book from time to time, you know, and it is nice if you can do so without breaking the end boards off. I sugggest you read this article by an expert book conservator:
http://www.bookthink.com/0071/71alt.htm
There is no evidence whatsoever that Lexol or any other saddle soap breaks down the leather to make it pliable or softens it by destroying any fibers.
First, Lexol is not a saddle soap. Lexol's own ads say: "Contains no harsh ingredients that can damage, discolor or dull leather like alkaline saddle soaps do." Unfortunately, those same ads then go on to make at least one statement that flatly contradicts what they said earlier. If all their claims for Lexol's verious uses are true, then it very plainly
does damage leather. I'll get to that later.
Second, do a google search for saddle soap and damage and you'll be overwhelmed with evidence. It's all over the place. The sole exception to this is a saddle soap with glycerine added, and even that won't work unless you
keep using it, because glycerine evaporates. It just does it a little slower than water (days instead of minutes). That is why they
make things like mink oil, Leatherique Rejuvenating Oil, Neats Foot Oil and etcetera. Heck, even
Lexol markets their own version of Neats Foot Oil.
Now about Lexol damaging leather. This is something I have been hearing from leather workers for years. Lexol's own advertising states that it won't damage leather fibers and yet that it shortens the break-in period for leather boots, gloves and etcetera. These statements directly contradict one another. You break in leather by repeatedly bending and breaking the fibers (thus the phrase "breaking in"). There is no other way to break in leather. Since it very plainly DOES shorten the break-in period of boots, gloves, and so on, then it makes the leather fibers weaker, so they break.
Lexol's advertising also states that it won't stain leather. Well, I keep reading on forums about people who are complaining that it turned leather dark. One guy, who used it on a vintage car seat, says it turned his gray seats black. He's trying to leach it out with alcohol.
"Hydroxypropyl_cellulose applied to leather would be similar to painting casein, latex paint or Elmar's glue on leather for restoration."
Hydro = water. Oxy = oxygen. Propyl = isopropyl alcohol. Cellulose = the vegetable substance that makes up cotton. Essentially, this is cotton that has been chemically proken down and made water soluable and it is dissolved in alcohol (which has the same density as water). I'm sorry, but your statement is just too ridiculous for words. The National Archives, the Smithsonian, too many museums to shake a stick at and rare book collectors all over the world
paint their books? They don't cover them in glue either. You dissolve Cellugel (a powder) in alcohol so it is thin and watery. It goes
into the leather, and you wipe it off. If you have done a poor job of mixing and there is anything on the outside of the leather, then you clean it up with more alcohol. It penetrates and
nothing is left on the surface. The alcohol evaporates, depositing cellulose
inside the leather. It is a very efficient binding agent and it coats the leather fibers
inside the leather. It holds the leather fibers together. On old leather that is dried out to the point the fibers are cracking you can not really rehydrate it. You can't make beef jerky into a steak. Cellugel it is also very flexible. Essentially, it is dissolved cotton. It holds the leather fibers together and restores some flexibility to them, by sheathing them in cellulose.
