ADDENDA ET CORRIGENDA. 
MR. BROUGHTON’S REPORT, AUGUST, 1868. 
Since the foregoing sheets were sent to press, I have received from Mr. Broughton a copy of his latest Report,* dated 17th August, 
1868. 
I am pleased to find that the contents of this letter tend greatly to the confirmation of the views I have advanced, especially 
in the following particulars : — 
1 . In reference to the value of the G. succirubra as a species for cultivation, which I have always thought over-estimated (and 
never more so than in recent accounts from Jamaica), Mr. Broughton says: — 
“ My experience of the Red Bark plantations does not lead to the conclusion that the amount of Quinine has shared in the 
increase observable in that of the other alkaloids. To this subject I shall subsequently return.” 
“Bark of C. succirubra, grown in the Wynaad at an elevation probably not exceeding 2400 feet, was thinner than that of Neil- 
gherry growth, and that of good appearance gave but 0*5 per cent, of Sulphate of Quinine, and 2’9 of Sulphate of Cinchonidine, 
showing that Quinine is formed in much less quantities at low elevations.” The whole of Mr. Broughton's experience leads to the 
conclusion that “ a high mean temperature is adverse to the yield of Quinine , but not to that of Cinchonidine .” 
“ The bark of two trees, after a sample had been analysed, was covered in one tree with a shield of tinned plate, and in the 
other with black cloth. The object was to keep the bark in darkness, while access of air was not impeded. The result of subse- 
quent analyses were as follows : — 
Total alkaloids .... 
Tree covered with tinned 
plate. 
Tree covered with black cloth. 
Original bark. 
Bark after 
ten months’ 
protection. 
Original bark. 
Bark after 
six months’ 
protection. 
Bark after 
ten months’ 
protection. 
5-29 
8-10 
5-04 
6-91 
7-92 
Quinine 
2T6 
1-65 
2-26 
2-03 
2-34 
Chinchonidine and Ckincho- 
nine 
3-13 
6-45 
2-78 
4-88 
5-58 
“ The foregoing experiments agree in showing that deprivation of sunshine has had the effect of increasing the amount of 
alkaloid in the bark. The alkaloid was obtained crystallized with nearly the same readiness as in mossed bark. The amount of 
Quinine has not, however, been increased, as in the case of mossing. This is a circumstance which I did not expect, and it is 
opposed to deductions from other experiments. It is, however, a fact, and will doubtless be explained by increased knowledge of 
the subject.” 
The trees covered with black cloth or with tinned plate, in this experiment, would not thereby be shielded from the heating' 
effect of the sun's rays, and probably on this account coincide in their product of Cinchonidine with those which I have described 
as grown in sunshine. 
u It is a fact that, in the Chinchona barks of South India (considered as a whole) , the replacement of Quinine by Chincho- 
nidine obtains to a greater proportion of the total yield of alkaloids than in those of South America. The actual amount of the 
substitution varies greatly in single trees, both according to its variety and the conditions to which it is exposed. The practical 
effect of this peculiarity is compensated for by the large total yield of the alkaloids. For medicinal purposes, it appears, from the 
recent medical trials, that it is of little importance which of the two alkaloids are produced. Nevertheless, the causes which 
produce the replacement are obviously of the greatest interest in connection with Chinchona cultivation. There must be several 
proximate causes, and it will, I think, be evident from the foregoing experimental results, that they are in progress of being 
elicited. Thus it appears that a low mean temperature within certain limits is favourable to the production of Quinine ,j* as is also 
* Proceedings of the Madras Government Revenue Department, September 22, 1868, No. 334. Read the following letter from J. Broughton, Esq., 
Quinologist to Government. 
f The italics are mine, to direct special attention to these important observations. — J. E. H. 
