102 2 
THE TROPICAL AGRICULTURIST. 
[June i, 1882. 
of attention. The Eurasian and Anglo-Indian Associ- 
ation might, at some future time, turn its attention to 
hop-farming on the Nilgiris. — Madras Times. 
TREE PRUNING. 
The secret of obtaining a complete cure in all oper- 
ations requiring the removal of a branch, either living 
or dead, consists in cutting close to, and perfectly even 
ivith, the trunk. Many authorities have hinted at this, 
the cardinal principal of all pruning ; but M. de Courval 
first clearly demonstrated its importance, while his dis- 
covery of the value of coal-tar or the refuse from gas- 
works as a covering for wounds made in pruning renders 
the application of his rule in all cases entirely safe. 
Formation of Wood. — The reason that a branch should 
be cut close and even with the trunk is found in one 
of the simple laws of plant life. It is known that sap 
has a double movement — that it mounts from the roots to 
the leaves, and returns again in an elaborated condition 
to the roots. Roots take up water from the soil in which 
there are various salts in solution. This water rises to 
the leaves; these absorb from the air and decompose 
carbonic acid gas, the basis of which is carbon, which 
combined with water constitutes the elements of w r ood. 
The sap thus elaborated by the leaves is earned down 
again in a liquid state, and is deposited, year after year, 
in the successive concentric layers of wood which form 
the trunks of all trees, with the exception of palms, 
yuccas, &c, which need not now be considered. 
It follows that a wound caused by the amputation of 
a branch must, in order to heal properly, be made per- 
fectly even with the trunk, that every part of its outer 
edge may be brought into direct communication with the 
leaves through the network of cells destined to convey 
the descending sap. Although this theory rests on one 
of the most elementary principles of vegetable physiology, 
it has not been applied before to practical forest manage- 
ment. The amputation having been made even with the 
trunk in the manner explained, new wood will soon 
appear, forming first round the top and sides of the 
wound, which is soon completely surrounded by the new 
growth ; the wound is gradually healed over, and the 
decay of the trunk prevented. The time required for 
the complete healing of a wound depends, of course, 
upon its dimensions and the natural vigour of the tree. 
The principle being established that large wounds can 
be made without injury to the tree if care is taken in 
the manner indicated to prevent decay, it is easy to 
show the advantage of cutting off injured branches of 
any size. It is preferable to avoid, of course, the 
necessity of making large wounds by properly pruning 
trees when young. All foresters agree that trees should 
be trained when young, but De Courval has amply 
demonstrated by numerous remarkable specimens exhibited 
at the Agricultural Show of Paris, in 1861, and at the 
Universal Exposition of London, in 1862, that it is 
beneficial, and often indispensable, to prune the oldest 
trees if care and judgment are used in the operation. 
He has clearly shown, too, that trunks so treated attained 
a larger size and a greater value in a given time than 
those which, under similar conditions of growth, had 
been allowed to retain all then- badly placed branches. 
I regret in this connection to difier from so eminent 
' an authority as De Breuil, who gives the following rule : 
"Amputations must be performed in such a manner that 
the diameter of the wound shall not exceed that of the 
end of the branch." Such a practice must, I believe, 
be disastrous, for whenever a branch of large size is 
amputated in this way, it is evident that a cavity in the 
trunk of the tree will sooner or later appear. 
It is only necessary to make the amputation even 
with the trunk and then cover the wound with coal-tar, 
to avoid all bad results. Although wounds caused by 
the amputation of small branches heal over in spite o 
the faulty methods of pruning generally employed, such 
operations are, nevertheless, attended with considerable 
danger to the tree. 
Experience and common sense show the objection to 
leaving any portion of an amputated limb, but there is 
greater danger in allowing stumps one or two feet long 
to remain on the trunk, a common practice even among 
persons interested in the preservation of trees. These 
stumps, deprived of communication with the leaves, 
die, the bark falls off, while the 6tumps themselves 
remain like plugs of decaying wood driven into the 
trunk. — Forestry. 
THE ALKALOID OF CUPREA BARK. 
TO THE EDITOR OF THE " PHARMACEUTICAL JOURNAL." 
Sir, — I am glad to observe from the concluding lines 
of your note appended to my last letter, that we have 
at least one point of agreement. Perhaps in time you 
will also recognize that if a compound is separable into 
" crystals of pure sulphate of quinine" and " a mother- 
liquor," it " can yield a crystalline sulphate which when 
isolated may be as loevogyrate as quinine sulphate, and 
give no hydriodate of quinidine ;" for surely, " pure sulph- 
ate of quinine," "when isolated," fulfils these condi- 
tions? At any rate this is the sulphate we obtained. 
By stating in our article that we had not succeeded 
in obtaining the new base, we did not question Mr. 
Howard's results ; for that chemist did not describe 
homoquinine as present in all cupreas, and he might 
have, and probably has, obtained it from some particular 
variety that had not then fallen into our hands. We 
have some reason for believing that Mr. Howard does 
not find homoquinine in the majority of the better 
sorts of cuprea, and so far therefore, we are simply in 
accord with hiin. That our statement might be con- 
sidered to cast doubt on the existence of his new 
alkaloid in cuprea barks generally, we do not deny, and 
I am even willing to emphasize this doubt, although 
I regret to find that I thereby put myself at issue with 
Mr. Whiffen. That anything like O'l per cent of a new 
base, crystallizable from ether, exists in the majority of 
good typical cuprea barks, I do not at present believe ; 
and I await with some curiosity the fuller researches on 
the new alkaloid, or alkaloids, that the authors will 
probably publish. Only the abstract of Mr. Howard's 
paper has as yet appeared; but in that certain definite 
characteristics of homoquinine are given. It will be 
interesting to see how far the base noticed by the other 
authors agrees with that of Mr. Howard in these char- 
acters of precision. 
At present Mr. Whiffen seems to attach chief im- 
portance to the loevogyrate character of the base he 
has obtained, but unfortunately his statements regarding 
this property are not sufficiently explicit. He operated 
on the " effloresced" sulphates of cmchonidine, quinine, 
and the new base ; but he does not state the com- 
position of the effloresced sulphate of the new base, i.e., 
the amount of water it retained, nor does he state the 
solvents used, although this is well known to greatly 
affect the angle. Mr. Whiffen gives for effloresced sulph- 
ate of quinine (a) j =196. Hesse gives for the anhydrous 
sulphate in alcoholic solution (a)j=191-47 and in acid 
solution (SO = 4 per cent of the sol.) («)j=228-78. 
Effloresced sulahate of quinine is stated to retain 2 mole- 
cules of water, and, therefore, according to Hesse's results, 
should give an alcoholic solution («)j=187, and in acid 
solution 218-49 ; the latter number being again subject 
to variation according to the proportion of acid present. 
I refer to these points not with the intention of casting 
any doubt on Mr. Whiffen's experimental observations, 
but to show the necessity for fuller details if chemists 
are to make any use of the numbers Mi-. Whiften has 
published. C. H. Wood. 
Sir, — In Mi-. Wood's letter to your Journal last week 
notice that he admits a doubt as to the existence of 
