On the Edulcoration of Fish- Oil . 337 
are not the same in both, it is proper to consider them dis- 
tinctly. 
Of alkaline salts it is the fixed kind only which are 
proper to be used for the edulcoration of oils. Fixed ah 
kaline salts, in a dissolved state, being commixed with 
putrefying animal substances, appear to combine with the 
putrid matter, and, mixing with some of the principles, 
form instantly volatile alkaline salts. On the less putrid 
they seem to act, after their combination, by an accelera- 
tion of the putrescent action, till they attain the degree 
which produces volatile salts. This is evident by the 
sensible putrid ferment and smell which appear after 
their commixture ; but which gradually abating, the oil 
is rendered sweeter, much lighter coloured, and thin- 
ner. 
Their great use in the edulcoration of fish-oil arises 
therefore from their converting such parts of the gelati- 
nous fluid and bile as are highly putrefied instantly into 
volatile salts, and causing a rapid putrefaction of the 
other parts : by which means the oil is freed from them 
by their dissipation. They do not, however, equally act 
on the parts of the oil on which the empyreumatic scent 
depends, unless by the assistance of heat : for when they 
are commixed with the oils without heat, in proportion as 
the putrid smell diminishes, that becomes more sensibly 
prevalent. The ultimate action of lixiviate salts on ani- 
mal oils, except with respect to the empyreunia, seems 
to be the same either with or without the medium of 
heat; for the same urinous and putrid smell, gradual di- 
minution of the colour, and foetid scent, happens in one 
case as in the other, except with regard to the accelera- 
tion of the changes ; and such salts, where the purifica- 
tion is required to be made in a great degree, are a ne- 
cessary means, as they are more effectual than any other 
substance that can be employed. 
ToL. IK T t 
