Question: What was saussage casing originally made from?
About the article "Sausage", section "Casings".

Candidate passages:
At completion, the Great Pyramid was surfaced by white "casing stones" – slant-faced, but flat-topped, blocks of highly polished white limestone.
These were carefully cut to what is approximately a face slope with a seked of 5½ palms to give the required dimensions.
Visibly, all that remains is the underlying stepped core structure seen today.
In AD 1300, a massive earthquake loosened many of the outer casing stones, which were then carted away by Bahri Sultan An-Nasir Nasir-ad-Din al-Hasan in 1356 to build mosques and fortresses in nearby Cairo.
The stones can still be seen as parts of these structures.
Later explorers reported massive piles of rubble at the base of the pyramids left over from the continuing collapse of the casing stones, which were subsequently cleared away during continuing excavations of the site.
Nevertheless, a few of the casing stones from the lowest course can be seen to this day "in situ" around the base of the Great Pyramid, and display the same workmanship and precision that has been reported for centuries.
Petrie also found a different orientation in the core and in the casing measuring 193 centimetres ± 25 centimetres.
He suggested a redetermination of north was made after the construction of the core, but a mistake was made, and the casing was built with a different orientation.
Petrie related the precision of the casing stones as to being "equal to opticians' work of the present day, but on a scale of acres" and "to place such stones in exact contact would be careful work; but to do so with cement in the joints seems almost impossible".
It has been suggested it was the mortar (Petrie's "cement") that made this seemingly impossible task possible, providing a level bed which enabled the masons to set the stones exactly. 
Company History.
Edwin O. Freund founder of what would become Viskase sought a readily available replacement for animal intestine casing.
Upon creating a cellulose casing, using the "viscose" process (also used in rayon) he realized the product stuffed well, linked, and was able to withstand the smokehouse.
Quite by accident, he discovered that when the casing was removed from the product the sausages retained their shape and were firm.
This was the beginning of the skinless frankfurter or hot dog. 
A Romanian clone.
The casing was adapted from a telephone. 
Bockwurst is a German sausage invented in 1889 by restaurant owner R. Scholtz of Berlin.
It is one of the most popular varieties within Germany, and can be found abroad.
The sausage is traditionally made from ground veal and pork (tending more towards veal, unlike bratwurst).
In modern Germany, however, it is made from different types of ground meat, such as pork, lamb, turkey, chicken and in rare cases even from horse meat.
In Northern Germany there is also a version of bockwurst which is made from fish.
Bockwurst is flavored with salt, white pepper and paprika.
Other spices, such as chives and parsley, are often also added and in Germany itself bockwurst is often smoked as well.
Bockwurst was originally eaten with bock beer and it is usually served with mustard.
A natural casing sausage, it is usually cooked by simmering although it may also be grilled.
When thoroughly cooked, its casing usually splits open.
Ideally, one stops cooking just before that occurs because the split casing may look unappetizing and the sausage may then lose flavor to the cooking water.
Bockwurst made in America, also from veal and pork, bears more resemblance to the Bavarian Weisswurst in color and taste, albeit parsley is rarely used in this version. 
TESCO was created in December 1993 when Shelter Oil and Gas Ltd., Coexco Petroleum Inc., and Forewest Industries Ltd. merged as Tesco Corporation, originally Tesco Drilling Technology, a joint venture between the three.
TESCO originally became famous for inventing the first portable land top drive, which won a Special Meritorious Award for Engineering at the 1994 OTC show.
Since then, TESCO has branched out into casing running as well, including a casing running tool called the Casing Drive System, or CDS.
In 2006, the company moved their headquarters from Calgary, AB to Houston, TX, while continuing to manufacture in Calgary.