62 ELEMENTS OF APPLIED MICROSCOPY. 



Starke) was originally derived. Its adhesiveness makes 

 it desirable for bookbinder's paste. Its stiffening power 

 gives it supreme importance in the laundry; for society 

 has not yet outgrown what the Puritan divine described 

 as "a certaine kinde of liquide matter which they call 

 starch, wherein the devill hath willed them to wash and 

 drie their rufHes, which when they be dry, will then stand 

 stiffe and inflexible about their necks." The quality of 

 forming a size gives starch an increasing importance in 

 cotton- and paper-mills, print-works and bleacheries. 



As a powder, stairch is used in many pharmaceutical 

 preparations, in baking-powders and other products 

 where some finely divided neutral substance is desirable, 

 and for powdering the forms in printing-houses. 



Finally, starch when heated in the dry condition to 

 i5o°-2oo° F. yields a soluble dextrin, sometimes called Brit- 

 ish gum, extensively used as a substitute for gum arable. 

 When treated with weak acids or with certain enzymes 

 starch is converted into dextrins and sugars and may thus 

 serve as the raw material for the manufacture of glucose, 

 maltose, and ultimately of alcohol. 



4. Microscopical Examination of Starch. — ^Since the 

 chemical composition of the various starches is identical, 

 the microscope offers the only satisfactory" means of 

 studying them. Fortunately the appearance of starch- 

 grains from the various groups of plants is quite charac- 

 teristic; and one familiar with the commoner forms can 

 easily detect the sophistication of other substances, like 

 mustard, by means of starch, the presence of foreign 

 bodies (minerals or seed-hulls) in starch, or the adul- 



