Memoir on the Nature of fat SuLstavces. S3 



also saturate one part of tlie properties of the sulphuric acid, as 

 they saturate that of the alkalies. Potash in saponifying pork 

 suet transforms it also into adipocire and oil *. The gray pa- 

 per in which tlie lard had heen compressed was strongly pene- 

 trated with oil ; it was moistened with hot water and subjected 

 to the action of the press, after having been inclosed in a strong 

 cloth, and we obtained an oil which was easily separated from 

 the water. The oil of lard is a colourless fluid like water, of a 

 peculiar taste. Wlien exposed to a greater degree of cold it 

 •does not freeze, if it has been obtained at a low temperature. 

 One hundred parts of hogs-lard at zero of the thermometer fur^- 

 nished me as constituent principles : 



Oil 62 



Suet 38 



100 

 If the compression of tlie lard has been effected at a middling 

 temperature, we obtain a greater (juantity of oil ; but in Hiis 

 case the latter retains some suet, and is hardened into a gela- 

 tiuous consistence when exposed to the cold. 



Beef Marrow. 



When slightly pressed between the fingers, this substance, 

 tiaken from the interior of the thigh-bone, seemed entirely formed 

 of an innumerable multitude of very distinct transparent bags 

 containing the marrow. We shall see presently that this struc- 

 ture is not peculiar to the marrow, but that it is common to all 

 fat substances in the animal kingdom. When well washed and 

 freed from its vascular envelopes by fusion, beef marrow had a 

 firm consistence at the tenipcrature of — "2" R. ; in this state it 

 was pressed in gray paper until it ceased to stain it, and I obtained 



►Suet 76 



Oil 24 



100 



* r had dissolved in a prrat quantity of lv.^ter, soap procnrpd from hogs- 

 lard and potash, with a view to fxaiiiiiie the substance descnlicii l;y AJ. 

 Chevreul uiidtT thf. name of Marj^arine; hut instead oK (ihtaininj) a pearly 

 suhstancc ill iiriiiiunt scales, nothing; was fdrnied alter some days hnt a 

 very triflin'^ prcripitate, which when coUccIed on the filter liad tlie ap- 

 pearance of <;i latnious albumen n(!wly precipitated; when dried, it was of 

 a dull white, which hecaiue shinintr wiien rnl)bed, and was redui.eil lietweeu 

 the fingers to an impalpable p<iwder, soft and soapy to tlie touch. This 

 matter, insoluble in water, was composed of an adipocirotis substance, 

 potash, and a small quantity of lime. Probably it is not this substance which 

 M. Chevrenl lias described as marj;arine: 1 confess caiiilidly that Iain 

 it;ti«rant of tde circumstances which ina)' havt cuncnntd in tiie formation 

 o\ tills last substance. 



Vol.4C. No. 207.^«/// 1815. C But 



