49 
A. scholaris, R.Br. ( Echites scholaris, Linn.), is a native of India, the Malay Archipelago, and 
tropical Australia. The wood of this tree has received the name lignum scholare on account of the slabs 
of the close-grained wood being used as school slates, the letters being traced upon them in sand. In 
Ceylon this light wood is used in making coffins. This tree which, as already mentioned, is widely diffused, 
attains a height of 50 to feet, and has a furrowed trunk. 
The Bark is known by the names dita bark, devil bark, and by the Indian names pali-mara, lutiana, 
chatin, and satwin. It is found in irregular fragments of -J- to i inch thick, and of a somewhat spongy 
texture, and having a coarse fracture. The outer surface is unevenly rough, and of a brownish-grey colour, 
while the internal layer is bright buff. It is important to bear these descriptions in mind, for several 
specimens have hitherto been placed on the market which are really A. spectahilis. The bark is not 
nearly so bitter as the barks from A. spectahilis and A. constricta. It has no aromatic, nor, in fact, any 
odour, and in this respect it differs from A. constricta. Underneath the rough external surface are cream- 
coloured patches which often peel off in flakes, and, indeed, two of the specimens I have are entirely made 
up of these cream-coloured patches. Mr. Holmes says he has often seen A. scholaris bark like these 
peelings, but really they are only part of the bark. 
Chemical 2’ests for the Bark. —(1) If strong H 2 SC >4 be applied to the inner layer of A. scholaris 
bark, a bright red colour is soon developed (ditamine test), which in a very short time changes to a dirty 
brown. This is a beautiful test if carefully applied. Should the inner layer happen to be blackened by 
dirt or age, carefully scrape away the dirt, then apply a drop of clear pure sulphuric acid to the clean spot. 
Wait one minute, remove the acid, by drawing the cleansed finger once across the acid, and if the bright 
red colour has not then developed, it will do so in a very few minutes. (Compare with A. constricta bark.) 
At first the colour often appears in small dots the size of a pin point, and then becomes general. Note .— 
The colour soon changes to dirty brown or some dark shade. (2.) Strong nitric acid applied to a similar 
surface gives very soon a yellowish spot (not bright red as in the case of A. constricta bark). If some of 
the nitric acid happens to have run in between the outer and inner layers, spots of dark blue may be seen. 
(3.) Tincture of iodine gives a black spot (compare with A. constricta). 
Chief Constituents. —O. Hesse found three alkaloids ditamine, echitamine and echitenine. 
Ditamine has the formula C 10 H 1S) NO 2 . It is soluble in most of the fluids employed in exhausting drugs. 
It is readily soluble in dilute acids. I prepared ditamine or some such alkaloid from A. scholaris by 
exhausting the powdered bark with boiling methylated spirit, evaporating the spirit to low bulk, and 
adding very dilute acid to take up the alkaloids. The caoutchouc, which was present in abundance, was 
removed; then the fluid was filtered, treated with purified and washed animal charcoal to remove the 
small amount of colouring matters. After filtering, a very bitter fluid was obtained. I next added 
ammonia in excess, and there was thrown down a white precipitate, which was bitter in taste; but not 
nearly so bitter as alstonine, the alkaloid of A. constricta. This precipitate was washed, dried, and tested 
for ditamine. With strong H 2 S0 4 it gave a bright red changing to various shades of violet on heating. 
With strong HN0 3 it gave a yellowish colour. These two tests, taken along with the precipitation from 
a mixture of all the alkaloids of A. scholaris by excess of ammonia point to ditamine. It is to be 
remembered that ditamine is white, while alstonine is brown in colour. 
Action of Ditamine. —This alkaloid is said to possess an action like curarine—that is, it paralyses 
the motor nerve endings. I have not experimented with it; but I intend to investigate the exact 
pharmacology of both ditamine and alstonine. 
Therapeutics .— Dita bark was introduced to Professor Christison’s notice nearly forty years ago, 
but I have been unable to find out what he thought of it. The tincture was prepared by Mr. Macfarlan 
about the same time, so that it has been known in Edinburgh for a long time. Since then it has had ups 
and downs, but has never been a general favourite. It is, perhaps at best, a good general tonic, which 
may prove useful in debilitating diseases. 
A. spectahilis, R.Br. ( Blaberopns venenatus, De Cand.), yields the poele bark of Java. It is closely 
allied to A. scholaris, and the one is sometimes mistaken for the other; but poel6 bark is much more 
bitter—in fact, in this respect, it resembles A. constricta. It yields six times more ditamine than dita. It 
is a native of Java, Borneo, and the “Challenger’ Expedition explorers found it in the South-eastern 
Moluccas. In that useful manual the “Treasury of Botany” it is stated that in Borneo the wood of a 
tree allied to A. scholaris is of a white colour near the root, and being very light is used for floats for nets, 
and household utensils, such as trenchers, corks, &c. This may lx* A. spectahilis. The two must be very 
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