SPECIES OP FECULA EMPLOYED IN PHARMACY. 27 
entirely destitute of it. The following is the explanation of 
the anomaly: 
The stem of the Orchis proceeds from a tubercle, by which 
it is nourished, and which is consequently exhausted daily. 
But in proportion as the stem rises, there is produced in the 
midst of many simple radicles, a new tubercle, which en- 
larges gradually, and survives the stem, as well as the original 
tubercle, in order to propagate the species. If it so happens 
that a chemist looks for fecula in the withered tubercle, he 
will certainly not find it; and it is probable that this was the 
case with Robiquet; but this same tubercle contained it before 
being exhausted by the nourishment afforded to the stem. If 
the new tubercle, when too young, be examined, again it will 
not be found. Hence it is necessary to collect the tubercles of 
the Orchis immediately after the flowers begin to fade; at 
which period the new tubercle is most rich in fecula and 
aroma. 
The grains of the fecula of the Orchis, examined after 
having in the form of salep been reduced by ebullition, appear 
spherical, and do not exceed (the largest at least) the T -J^ of a 
millimetre; in some species they are even the ^1^. 
Table of the greatest dimensions of the grains of feculse 
ew 
Names of Plants. 
Solatium tuberosum, 
Potato. 
Cycas circinalis, 
Sago. 
Avena sativa, 
Oat, 
Triticum sativum, 
Wheat, 
Secale cereale, 
Rye, 
Maranta arundenacea, 
Arrow root. 
umerated. 
Organs, Dimensions. 
Tubercles, § 
Medulla, 
Seeds, 
Perisperm, 
do. 
do.} 
do. $ 
Root, 
i 
JL to 
1 \ lVJ 3 3 
d0. \ ^0 
do. 
