t 9 S MATERIA MEDIC A. 
white colour, brittle and eafily pulverized ; of this 
very little is to be found in large quantities in the 
common Frankincenfe, and is hot to be feparated 
from it, unlefs it be particularly defired for the 
Apothecaries Ihops. 
An Example of the nutritive Virtue of Gum 
Arabic. 
The Abyflinians make a journey to Cairo eve- 
ry year, to fell the products of their country: 
Slaves , Gold , Elephants , Drugs, Monkeys, Parrots, 
&c. They muft travel over terrible defarts, and 
their journey depends as much on the weather as a 
voyage at fea, confequently they know as little 
as a feaman how long they muft be on the journey* 
and the neceffaries of life may chance to fail them* 
when the journey lafts too long. This happened 
to the Abyffinian Caravan in the year 1750, their 
provifions being confumed, when they had ftill 
two months to travel ; neceffity obliges us often to 
ufe things for food before unheard or unthough £ 
of; this happened in the cafe in queftion ; the/ 
were obliged to fearch for fomething amongft their 
merchandize, wherewith they might fupport life i fl 
this extremity, and found nothing more prope r 
than Gum Arabic, of which they had carried a 
confiderable quantity with them. This ferved £<? 
fupport above roooperfons for two months. 
Gum Arabic is gelatinous, and undoubtedly con* 
tains l'ome nourifhing particles. But here we m^/ 
afk, Whether this food did not make thefe p°° r 
people very coftive ? It muft in all probability ha ve 
had this effect, but of this I could not learn a 11 / 
circumftances. I know however, that the Cara- 
