190 Soap. 



1st. That the discovery of a small number of species of 

 fat bodies, susceptible of uniting together in indefinite pro- 

 portions, explains the differences of fusibility, odour, and 

 taste, which are found in the prodigious quantity of tallows, 

 fats, butters, and oils, which are met with in organized 

 bodies, and at the same time, it reduces to the laws of definite 

 combinations, an entire class of substances which seemed to 

 be withdrawn from it. It is evident that stearine, oleine, 

 butirine, phocenine, piscine and cetine, are to the tallow, 

 fat, butter, and oil, which they constitute, what those metals, 

 which, (like tin and lead, tin and copper,) are capable of 

 uniting in indefinite proportions, are to their alloys, 



2d. That the species of fat bodies which I have established, 

 form in organic chemistry a new class of substances which 

 present groups extremely distinct from each other: thus we 

 have fat bodies which are acids, and fat bodies which are 

 not so. Among the former are found, 1. the stearic, mar- 

 garic, and oleic acids, which, relatively to the manner in 

 which they are affected by heat, correspond with the benzoic 

 acid ; 2. tlie volatile acids, of which I have spoken in the 

 memoir, which correspond with the acetic acid. Among 

 the fat bodies not acids, there are some, as cholesterine and 

 ethal, which experience no alteration by the most powerful 

 alcalies, whilst others, as stearine, oleine, butirine, phocenine, 

 and hircine, are all converted, under the alcaline influence, 

 into a mild principle on the one part, and into fat acids, fixed 

 or volatile, on the other part ; and it is not impossible that 

 this last species may be constituted immediately by the 

 same acids, and a mild anhydrous principle, which performs 

 the functions of a base. However this may be, we cannot 

 avoid considering the substances which produce odoriferous 

 acids by saponification, as resembling others, which are 

 regarded as compounds of acids and alcohol. It is very 

 probable ih^i butirine - such as I have prepared it, is a union 

 of several species of immediate principles, each of which is 

 characterized by the property of wines reduced, under the 

 alcahne influence, into a mild principle, and a single volatile 

 acid. 



