PHILOSOPHICAL TRANSACTIONS. 
I. Chemical and Physiological Experiments on living Cinchona ?. Eg J. Broughton, B.Sc ., 
F.C.S., Chemist to the Cinchona-Plantations of the Madras Government. Commu- 
nicated by Dr. E. Frankland, F.B.S. 
Received May 16, — Read June 16, 1870. 
On the Neilgherry Mountains in South India are now growing nearly three millions of 
trees of cinchona of various species. The greater part of these are on plantations 
belonging to Government, and are the result of the introduction from South America 
and successful naturalization of these valuable febrifuge-yielding plants by the Govern- 
ment of India, under circumstances which have long since been made public. 
The chemical investigations which during the last three years have been made, for the 
purpose of settling the various economic questions connected with the production of the 
febrifuge constituents of the bark, have led to some conclusions of scientific interest. 
I have the honour in the subsequent pages of communicating to the Royal Society the 
most important of these, and the experimental grounds on which they depend. These 
inquiries have been made under circumstances of great advantage, for the living plants 
have never before been under the control of the experimenter. The ability to study the 
changes occurring in the growing tissues cannot fail to throw light on the formation and 
physiological functions of the chemical constituents whose production is the object of 
the undertaking. 
The organic principles which characterize these cinchona-barks are the alkaloids 
Quinine, Cinchonidine, Cinchonine, and occasionally Quinidine, the peculiar bitter 
principle Quinovin, the acids Quinic and Quinotannic, and in small amount another 
not fully investigated. 
Without attempting to describe the well-known alkaloids, it may be stated that all 
the facts known point to a marked natural connexion between quinine and cinchonidine, 
notwithstanding the difference of an atom of oxygen in their composition. Thus the 
analysis of the individual plants will frequently give results which show the same amount 
of alkaloids, but which differ by the respective quantities of these alkaloids, while all 
MDCCCLXXI. b 
