138 OLEOMARGARINE. 



in sufficient quantity to saponify all the butter fat treated, the alkaline 

 base unites with the soluble fatty acids, and what is left undecomposed 

 are the fats containing the insoluble fatty acids. He also illustrates 

 this by relating an actual experiment. This strongly corroborates the 

 supposition that it is the butyrin that is first broken up in the stom- 

 ach and intestines. 



"We have een in the process of stomach digestion that some fat 

 was emulsionized and broken up into its acid and glycerin constituents. 

 So we have butyric acid set free in the stomach to unite with a base 

 from some of the weaker salts, as the carbonates, for instance, to form 

 a very soluble soap which is dissolved by the bile as soon as it comes 

 in contact with it, and thus furnishing, even a fresh butter, the most 

 favorable conditions for starting the action of the pancreatic juice upon 

 fats. Indeed Roberts claims that a small admixture of a free fatty 

 acid in the chyme, together with the agitation produced by the move- 

 ments of the intestines, is sufficient to emulsify fats without the aid of 

 pancreatic juice. 



"Routh also declares the same. None of the other animal fats con- 

 tain butyrin. 



"The large proportion of but}^rin in butter and its nonoccurrence 

 in any of the other animal fats, together with the volatility of its acid, 

 has long impressed us with the belief that it had some important office 

 to perform in the digestive process. Under this belief we began a 

 series of experiments upon the artificial digestion of different fats. 

 Our digestive fluid was composed of 5 grains of Fairchild Bros, and 

 Foster's 'Extractum pancreatis,' 5 grains of bicarbonate of soda dis- 

 solved in 10 c. c. of distilled water. After the solution was complete 

 we added half a dram of melted fat. 



"The whole was well agitated in a test tube and placed in an oven 

 at a temperature of from 100 to 101 F. The fats experimented on 

 were cod-liver oil, butter, oleomargarine butter, the commercial oleo- 

 margarine oil, lard oil, benne oil, cotton-seed oil, lard, and mutton and 

 beef suet. The cod-liver oil was bought from a reliable drug store. 



"Both fresh and stale butter was used, and was such as we had made 

 ourselves, seeing the milk from which it was made drawn from the 

 cow, or such as we had analyzed ourselves and found to be pure cow's 

 butter. Fresh and stale ' oleo ' was used, and was also either made by 

 ourselves under the 'Nathan' patent, which 'oleo' contained some free 

 acid, or was that which we had analyzed. The oils were all obtained from 

 'oleo' makers or dealers in New York City. Both the pure, washed, 

 dry fats of the butters and 'oleos' and the natural products were com- 

 pared, as will be described directly. The contents of the test tubes 

 were examined under a microscope at intervals of one, two, three, 

 four, six, twelve, sixteen, and twenty hours. 



"The cod-liver oil nearly always showed the finest emulsion. 



"Next, and the difference was often just perceptible, came genuine 

 butter. 'Oleo' and lard oil came next, there being frequently no 

 appreciable difference between them, but between the butter and the 

 'oleo' there was a marked difference at the end of each period. 



"Fig. 4, PI. I, and fig. 1, PI. II, shows the difference between 

 'oleo' and genuine butter after being acted upon by the digestive 

 fluid for one hour. It will be noticed that there is no emulsion at all 

 of the ' oleo,' while the butter is well advanced. 



"Fig. 5, PI. I, and fig. 2, PI. II, shows the same at the end of four 



