*208 Proceedings of Societies. 
the natives are suspected of breaking the leaves, so as to prevent a discovery of 
the plant from which they are obtained. The leaves of the Mati are prepared 
for making the tea in the following manner : A long cylindrical furnace is con- 
structed, termed a barbagna, in which a bright fire is made with the dry branch- 
es, from which the leaves had previously been separated. When this furnace is 
sufficiently heated, the leaves are spread on metallic plates, so that they do not 
touch each other arid are then introduced into it. An attendant called quayno, if 
expert, will prepare twenty-five pounds a day. The dried leaves are packed in 
cotton bags of a large size. 
The people of South America attribute the most astonishing properties to the 
Mati, and use a very large quantity of it. If it be taken in moderation, it causes 
excitement and watchfulness, but if it be taken in excess, it produces drunken- 
ness and tremors, resembling those induced by the abuse of spirituous liquors. 
Opium appears to cause opposite effects, and is therefore used as a remedy to 
obviate the injurious consequences induced by the Mati. 
Dr Sigmond afterwards proceeded to lay before the society the results of a se- 
ries of experiments on copaiba, conducted in Mr Battley's laboratory. From 
these it appears that trituration of the copaiba with magnesia, then making a 
tincture with proof spirit, and adding a little nitrous ether after filtering the spi- 
rit, affords the best preparation of the balsam. From one drachm to four, two 
or three times a day, is the dose. 
Professor Johnson then delivered a lecture on the philosophy of botany, after 
which the meeting adjourned Communicatedby Mr Foote, oneofthe Secretaries. 
EDINBURGH. 
ROYAL SOCIETY, March 21, 1836 Rev. Dr Chamlers, V. P. in the Chair. 
Observations and experiments on the coloured and colourable matter in the 
leaves and flowers of plants, particularly in reference to the principles upon 
which acids and alkalis act in producing red and yellow or green, (continued 
from 18th January.) The paper terminated with the following general conclu- 
sion, that there exist in plants two distinct colourable principles, two species of 
chromogen, one which generates red compounds with acids, and denominated 
Erythrogen ; and another which forms yellow compounds with alkalis, called 
Xanthogen. That these two principles occur together in red and blue flowers, 
and in the leaves of a few plants, which exhibit the former of these tints ; that 
all green leaves, all white and all yellow flowers, and white fruits contain xan- 
thogen alone ; that litmus abounds in erythrogen but has no xanthogen ; that 
the chromules of different tints may be generally considered distinct vegetable 
principles, or compounds having their own proper hue ; sometimes intimately 
blended, or chemically combined with chromogen ; at other times having no con- 
nection with it ; that they are also occasionally, but not frequently, compounds 
of chromogen with acids or alkalis. The paper will be continued. 
April 4, Dr Hope, V. P. in the Chair. Communication " On the newly dis- 
covered Microscopic Entozoon infesting the Muscles of the Human Body, by Dr 
Knox." 
April 18, Sir T. M. Brisbane, President in the Chair. Mr Stark read a 
communication from Dr Parnell, on the occurrence of the Clupea alba or white- 
bait, and of the Raniceps trifurcatus or tadpole fish, in the Frith of Forth. 
May 2, Sir T. M. Brisbane, President, in the Chair. Dr Knox exhibited some 
specimens to prove that the teeth of the Cachalot are devoid of enamel Pro- 
ceedings of Royal Society, Edinburgh, No. 9. 
