156 CHEMICAL TRANSFORMATIONS IN 



centrations) by P E , P A , and P B , for ester, acid, and base respec- 

 tively, then the equation of equilibrium for the ethyl butyrate and 

 monobutyrin becomes P E = K . P A . P B or P E =K . P 2 A , and that 

 for the neutral fat is P E =K . P 3 A . P B , or, assuming that the con- 

 stituents are present in the proper concentrations for combination, 

 P E =K . PV 



Contrasting the two formulae P E =K . P A 2 and P E =K . P A 4 , we 

 see that in the case of such a reaction as that in which a neutral 

 fat is formed, the tendency to remain dissociated in dilute solution 

 and to remain combined in concentrated solution is more exag- 

 gerated than in the simpler reaction. Accordingly, as we pass 

 from a concentrated solution to a dilute solution the value of P E 

 falls very rapidly compared to the fall in P A , or the relative amount 

 of neutral fat becomes very small. In excessively concentrated 

 solution practically all would be neutral fat, but very rapidly on 

 reducing the concentration nearly all would be hydrolysed to free 

 fatty acid and glycerine. 



Hence a synthesis of neutral fat from fatty acid and glycerine 

 is only possible in a highly concentrated solution. But the physical 

 property of the fatty acids and neutral fats of being insoluble in 

 water renders the attainment of such concentrated solutions an 

 impossibility in all attempts at synthesis hitherto made, and for 

 this reason no satisfactory proof of syntheses of neutral fats by 

 lipase have hitherto been furnished. 



The theory of equilibrium in solution proves, however, that 

 given the possibility of obtaining more concentrated solutions of the 

 fatty acids, the synthesis of neutral fats by enzymes is quite possible ; 

 and in the conditions obtaining in the cell, where the solvent is not 

 water but the cell protoplasm, and where also other solvents, such 

 as the bile salts, may be present in concentrated solution, the syn- 

 thesis of fats may well occur by such means. 



The synthesis of neutral fat from soap and glycerine solutions 

 has been claimed by C. A. Ewald, and by Hamburger, by the 

 action of the isolated cells of the intestinal mucous membranes; 

 but similar experiments by the writer, in which both the cells and 

 cell- free extracts of the cells were used from the intestinal mucosa, 

 lymphatic glands, and the pancreas, demonstrated that no trace of 

 neutral fat was ever formed, the only action observable being a 

 setting free of fatty acids from the soaps used. The observations 

 of the authors quoted above, being obtained by difference between 



