NON-PROTOPLASMIC CELL CONTENTS 85 
loidal reagents: tannic acid, gold chloride, phospho-molybdic 
acid, picric acid and potassio-mercuric iodide (Maver’s reagent). 
EXAMPLES OF ALKALOIDS 
_ STRYCHNINE—This alkaloid, with a chemical formula of 
C2:H»2N2Oz, occurs in the seeds of Strychnos Nux-vomica, Strychnos 
~ Ignatii and other species of Strychnos. When sections of strychnine 
containing seeds, previously defatted with petroleum ether and 
absolute alcohol, are mounted in a solution of 1 Gm. ammonium 
vanadate in 100 cc. of sulfuric acid, they take on a violet-red 
color which later changes to brown. Strychnine itself produces 
with sulfuric acid containing 1 per cent. ammonium vanadate a 
deep violet-blue color changing to a deep purple and finally a 
cherry red. It crystallizes from alcoholic or aqueous solutions, 
forming rhombohedral crystals. 
Brucine—This is another alkaloid obtained from Strychnos 
seeds having the formula of C23H2¢O4Ne. It crystallizes from 
watery solutions in the form of monoclinic prisms. Nitric acid 
imparts to it a red color. 
Nicotine.—This is a volatile alkaloid having the formula of 
CioHi4No which is found in the Nicotiana genus of the Nightshade 
family. Sections of tobacco leaves or stems mounted in dilute 
Lugol’s solution will show first a carmine-red color and then a 
reddish-brown precipitate which in time loses its color. 
CAFFEINE.—This alkaloid, with a formula of CsHipNsO2 + 
H.O, occurs in Tea, Coffee, Maté or Paraguay Tea, Cassine, 
leaves of Ilex vomitoria or Yaupon, and seeds of Kola, Cocoa, etc. 
If thin sections containing it are placed on a glass slide in 2 or 
3 drops of concentrated hydrochloric acid and gently heated and 
then 2 or 3 drops of gold chloride solution are added, the sections 
then pushed to the side and the liquid allowed to evaporate, 
slender, yellowish, branching needles of caffeine gold chloride 
will be seen to separate. 
CocaInE.—This narcotic alkaloid, having the formula 
Ci7HeiN' Ou,, is found in the leaves of Erythroxylon Coca and E. 
Truxillense. If sections of these leaves are prepared in the same 
manner as indicated for those containing Caffeine, but platinum 
chloride solution substituted for that of gold chloride, large 
