82 PHARMACEUTICAL BOTANY 
BEAN STARCH (Phaseolus vulgaris) 
Ovoid, ellipsoidal or reniform shaped 
simple grains, occasionally obscurely 
3- or 4-sided. 
Up to 60y in length. Generally from 
30-35. 
Hilum: central, elongated with bran- 
ching clefts. 
Lamellz: distinct, concentric. 
indistinct. 
Polarization crosses shaped thus, x. 
In some 
PEA STARCH (Pisum sativum) 
Oval-oblong, elliptical or sub-reniform. 
Up to 51y in length. Generally from 
20—40u. 
Hilum: similar to that of bean starch 
but less cleft or simply elongated. 
Lamellz: distinct, concentric. 
Polarization crosses similar to - bean 
CANNA STARCH (Canna edulis and other 
species of Canna) 
Broadly elliptical, flattened, with beak 
or obtuse angle at one end. 
Most grains 50 to 135y in length. 
Hilum: excentric near narrower end. 
Lamellz: concentric and eccentric. 
Polarization cross very distinct; fine 
play of colors with selenite plate. 
Saco Starcu (Metroxylon Sagu et al. spp., 
Cycas spp.) 
Ovoid, muller-shaped, or irregularly 
3 or 4 sided with rounded angles. 
Some more or less gelatinised. 
Simple or 2, 3 or 4-compound. 
Larger grains 30—60u long. 
Hilum: excentric, often altered by 
gelatinisation. 
Lamellz: eccentric and concentric. 
starch. Polarization cross distinct. 
3. Dextrin.—Dextrin is a carbohydrate made from starch 
(chiefly from corn or potato starch) by the application of heat 
(yellow dextrin) or by treatment with both heat and acids (white 
dextrin). It forms a paste with water, the yellow variety tending 
to swell up and dissolve much more readily than the white. 
When examined microscopically in alcohol mounts, the grains, 
while conforming in general outline to those of the type of starch 
from which the dextrin was prepared, nevertheless show more 
conspicuous striations and clefts. Corn dextrin shows distinct 
striations, whereas striations in corn starch are absent. The 
grains take on a red coloration with iodine solutions, 
4. AMYLODEXTRIN.—This is a carbohydrate intermediate in 
properties between starch and dextrin. It occurs in the form 
of small, irregularly shaped granules, in Mace, that take on a 
reddish brown to reddish violet color with iodine solutions. 
5. Inutin.—Inulin is a carbohydrate isomeric with starch 
which has the_chemical formula of CuBr. It is found 
dissolved in the cell sap of many plants, especially those of the 
Composite. If pieces of a plant part containing this substance 
be placed directly in alcohol for at least a week, then sectioned 
and mounted in alcohol, sphzro-crystals of inulin will be seen 
