EXPERIMENTS ON LIVING CINCHONA!. 
13 
the ash obtained when the plants are burnt. The alkaloids possess most of the general 
properties of these mineral bases ; they completely neutralize acids, and as they com- 
port themselves in a manner chemically so similar, it is thought that their functions 
are identical, and that certain plants are enabled to produce in their own economy 
actual substitutes for these necessary mineral bases, which are frequently but meagrely 
furnished by the soil in which the plants grow. 
The experiments of Puttfarcken (Pharm. Journ. vol. xi. p. 129) appear to corroborate 
this hypothesis. They were performed with the dry Calisaya - bark from South America, 
and appeared to show in the main that the bark yielded ash in inverse degree to the 
amount of organic bases. 
The simplicity and beauty of this hypothesis has always rendered it, in the absence 
of more precise information, a favourite one. On my first acquaintance with living- 
cinchona {par excellence the alkaloid-producing plant), there were several circumstances 
which seemed to show its truth ; among these were the exceptionally large yield of 
alkaloid in the Neilgherry cinchonas, combined with the singular poverty of the soil in 
lime. These circumstances led me to institute a series of experiments, in which the 
amount of organic bases was compared with the amount of ash yielded by the same bark ; 
this has been carried on with all the species of cinchona, and all the diversity of con- 
ditions I could devise. It is assumed as practically true that the amount of ash is pro- 
portional to the amount of mineral bases ; and it has been ascertained by experiment 
that the amount of ammonia is nearly constant, and is too small to vitiate the results. 
The following Table expresses the results obtained : — 
Alkaloids, 
per cent. 
Ash, 
per cent. 
C. SUCCIRUBRA. 
C. succirubra 
June 
1867 
5-05 
2-51 
from Co or<r 
July 
August 
5-03 
2-93 
7-80 
o 
orowinp- at. 7770 feet 
2-38 
,r 7660 
„ 5450 
4-21 
o*35 
Sentember .. 
4-00 
2-00 
„ 2300 
November 
4-10 
2-43 
» 6900 
rk 
March 
1868 
5-86 
3-17 
Mossed ha 
10-72 
2 -25 
Bark renewed under moss 
8-22 
2-20 
May 
March 
1869 
9-27 
2-52 
Trunk-bark. 2 vears old 
1868 
6-40 
3-60 
3-15 
3 “ 
6-09 
4 
7-40 
2-63 
Mean ,, 
1870 
7*55 
2-81 
ef „ 
6-23 
2-93 
2-97 
„ 
7-33 
3_l 
7-61 
3-09 
OL 
Q .0 1 
4-43 
Mean bran 
2 71 
ch-bark, 2 ^ vears old . 
April 
1868 
1-91 
4-31 
4-71 
3-13 
3 I " 
7- 
1870 
3*20 
4-92 
5*00 
6 1 
2-63 
5— 
3- 07 
4- 96 
0-81 
3-64 
3- 
3-42 
3 I 
5-03 
" 
