In spite of its great variety and wide distribution in nature, there 
are comparatively few sources of commercial starch. £ By far the greatest 
amount manufactured in the United States is made from corn, which averages 
about 55 percent starch. Considerable potato starch is also made in this 
country, as well as some wheat starch. Tapioca (cassava) and sago starches 
are imported to some extent from the Far East. The latter is used particu- 
larly in the manufacture of envelope gums. Cassava starch is noted for the 
uniformity of its paste. Of these starches, cassava is most often used in 
the production of vegetable glues for woodworking, although other starches 
can be used for this purpose. 
The general principles- of starch manufacture are: (a) Disintegrating 
the plant tissue in such a way that the starch grains are set free but not 
ruptured; (b) separating the starch from the gluten by diluting with water 
the disintegrated mixture, which has been previously treated with chemicals 
or subjected to fermentation, and by then settling out the heavy starch by 
subsidence; (c) washing the starch by agitating with water in tanks, 
"running," or decantation; (d) recovery of the starch by draining in cloth- 
bottom boxes or in deep frame filter presses; and (e) drying the starch in 
kilns. 
The starches from different sources will, of course, vary in certain 
properties; and, in addition, there may be variations in the starch from 
any one source depending upon growth conditions and on the methods and the 
care used in the production. Some of the starches, such as cassava, are 
marketed in different grades, and it is reported that the grade of the 
starch influences the properties of the adhesive. 
Development of Adhesives from Starch 
The use of adhesives from starches or sugars is supposedly a very 
ancient practice, although in woodworking industries it is a comparatively 
recent one. In connection with the early history of paper making it is said 
that the Egyptians used thin sheets of papyrus bound together with an adhe- 
sive made from a starch base. It is further reported that Chinese, 
centuries ago, used starch in some form for gluing wood. In more recent 
times attempts were made to use sugars as a base for an adhesive. In I89I a 
patent was granted to Higgins on an adhesive of dextrin and borax, and 
another in 189^ to Wagner on an adhesive of dextrin, copper sulphate, sugar, 
and nitric acid. An early United States patent on the use of starch as an 
adhesive was issued to Murphy in 1896. Bloede reports that a French patent 
was issued to Gerard in 187^ on a glue consisting of 1 part potato starch, 
5; parts water, and 0.08 part caustic soda. It is probable that these 
earlier adhesives did not have sufficient strength to warrant their use as 
glues for woodworking. In I908 a patent covering vegetable glue was issued 
to Frank G. Perkins. Under this and later patents the Perkins company 
2 
-Rogers, Allen. Industrial Chemistry; A Manual for the Student and 
Manufacturer. 6th ed. Van Nostrand, New York City. 19^2. 
Report No. R30 -2- 
