160 REPORT—1840. 
On the Chemical and Medicinal Properties of the Matias Bark, which 
is employed in Columbia, South America, as a substitute for Cinchona. 
By Dr. Mackay. 
The nature of the tree which produces this bark has not been as- 
certained, but from an examination of the properties of the bark, it is 
in all probability correctly supposed to be of the family Winteracez. 
The bark is sent to this country in pieces, which differ much in 
size and form. Its colour is either a pale fawn or brown internally, 
and brown externally. It has an agreeable and aromatic smell, and a 
bitter and rather pungent taste. 
When distilled with water it yields a considerable quantity of essen- 
tial oil, which separates into two distinct portions, one floating upon the 
surface of the water which distils along with it, while the other sinks 
to the bottom of the receiver. These oils differ in colour, in smell, 
and in specific gravity. 
Eight pounds of bark yield one pound of watery extract, which has 
an intensely bitter but agreeable taste, and a deep black colour. By 
acting upon this extract with ther, adding a large quantity of distilled 
water, then filtering and evaporating to dryness repeatedly, the bitter 
principle was, it is conceived, obtained free from impurity, with the ex- 
ception of colouring matter, which it has been found impossible to se- 
parate, on account of both being simultaneously taken up by animal 
charcoal. 
The bitter principle, as thus obtained, is a brown extractive sub- 
stance, soluble in zether, alcohol and water, which possesses neither acid 
nor alkaline properties, but has an intensely bitter taste. 
From the investigation which has been made into the properties of 
this bark, in several public institutions, they are ascertained to be tonic, 
febrifuge and carminative, or stimulant. It has been successfully ad- 
ministered in intermittent fever, in convalescence from continued fever, 
in hemicrania, in dyspepsia, and in a variety of chronic affections in 
which tonics and stimulants were indicated. As an adjunct to diuretic 
medicines it has been found eminently useful. 
The author exhibited specimens of the bark, of the oils, bitter 
principle, watery extract, and essence obtained from it, and concluded 
by expressing his deep obligation to R. Mackay, Esq., British Consul 
at Maracaibo, and to Signor Gonsales, for having devoted much time 
and attention in procuring for him the valuable substance, which he 
had now the honour to introduce to the notice of the profession. 
On the Laws which govern Contagious Fevers, the circumstances which 
favour their diffusion, and the mode by which they are communicated 
from one individual to another. By Dr. Perry. 
After some remarks showing that there was nothing peculiar to 
Glasgow in the site or want of cleanliness that was not to be met with 
in other large cities, he concluded that the chief cause of the diffusion 
of contagious fevers arose from the poor crowding into Glasgow from 
