VEGETABLE CYTOLOGY 
49 
sample of food or drug. The following characteristics should be 
noted in determining the identity or source of the starch. 
1. The shape of the grain. 
2. Whether simple or compound or both; if compound, the number 
or range in numbers of grains composing it. 
3. The size of the grain in microns. 
4. The position of the hilum, if distinct; whether central or excen- 
tric (outside of the center). 
5. The shape of the hilum and the degree to which it is often 
fissured. 
6. The nature of the lamellae, whether distinct or indistinct; if 
distinct whether concentric (surrounding the hilum) or eccentric 
(apparently ending in the margin and not surrounding the hilum), 
or both, as in potato starch. 
7. The color of the grains when stained with dilute iodine solu- 
tions; whether indigo, blue, purple, red or yellowish-red, etc. 
8. The appearance under polarized light. 
9. The temperature at which the paste is formed. 
to. The consistency of the paste. 
Characteristics of Important Commercial Starches 
Potato Starch ( Solatium tuberosum) Lamellie: concentric and eccentric. 
Mostly simple, conchoidal or ellip- Polarization cross very distinct; 
soidal, with occasional spheroidal 
and two- to three-compound grains. 
beautiful play of colors with 
selenite plate. 
Size: 5 to 125/1 
Maranta Starch ( Maranla 
Hilum: circular at smaller end of 
grain. 
arundinacea ) 
Fig. 16. — Potato Starch. ( X 250.) 
(Sayre.) 
Fig. 17. — Maranta Starch. (+250.) 
(Sayre.) 
4 
