204: STARCH. 



six to eight times its weight of acetic anhydride in 

 sealed tubes to 180, and treating the syrupy product 

 with water. White, flocculent mass, insoluble in water, 

 alcohol, and ether ; soluble in concentrated acetic acid. 



13. Starch (Amylum). 

 (C 6 H 10 5 )*. 



Occurrence. Very widely distributed ; in large quan- 

 tity in the seeds of the different varieties of grain; in 

 leguminous plants, chestnuts, potatoes ; in the trunks of 

 a number of pines, etc. ; further, in most roots, in a 

 great many kinds of bark, even in fruits, for example 

 in apples. Always deposited in plant cells, in the form 

 of microscopic grains. 



Extraction. Technically it is prepared from wheat 

 and potatoes by washing. They are ground, and the 

 starch grains washed out from the cellular substance in 

 a fine wire sieve. The starch settles from the milky 

 water as a white, solid sediment, which is repeatedly 

 stirred up with water, washed out and finally dried in 

 the air. 



Sago, from the pith of the sago palm, cassava and 

 tapioca, from the poisonous root (containing hydrocyanic 

 acid) of Jatropha Manihot, and arrowroot, from the root 

 of Maranta arundinacea, consist of the same kind of 

 starch. 



Properties. Perfectly white powder, glistening in 

 sunlight, consisting of small, shining, transparent 

 grains, recognizable under the microscope. These are 

 formed of layers, arranged upon each other, surrounded 

 by a more delicate and compact envelope, which is, 

 perhaps, cellulose. The grains are of various sizes and 

 forms, sometimes spherical, sometimes spheroidal, accord- 

 ing to the plant from which they take their origin. 

 Tasteless, inodorous, insoluble in cold water. Insoluble 

 in alcohol and ether ; these, however, usually extract 

 from most starch small quantities of wax and fat. 



Heated with water to 60, the envelopes are burst 

 and the starch forms a gelatinous, translucent mass. 



