SYNTHESIS OF FATS ACCOMPANYING INTESTINAL ABSORPTION 25 
In a later paper, Loevenhart 1 found a similar action in varying degree with 
extracts of intestinal mucosa, lymphatic glands, lymph, liver, kidney, submaxillary 
gland, lung, brain, adrenal and subcutaneous connective tissue. Similarly, 
Hanriot 2 found that pancreatic lipase synthesized monobutyrin from butyric 
acid and glycerine. 
It is, however, exceedingly dangerous, as is obvious on comparing the above- 
mentioned results with those obtained in the present investigation, to draw 
conclusions as to the hydrolysis or synthesis of one ester, from that of another. 3 This 
is true, even when all the constituents of the reaction are soluble, as even there the 
position of the point of equilibrium, as experiment shows, may vary enormously with 
different esters and be placed practically at either end point of the reaction ; but the 
proceeding becomes entirely misleading when the comparison is made between such 
dissimilar esters as the body fats and ethyl butyrate, where in the former action two 
of the three components are practically insoluble, and in the latter all three are 
easily soluble. Nor does it seem at all justifiable without experimental evidence to 
assume that the same catalyser, lipase, can in the intestine cause an equilibrium lying 
(in the case of the neutral fats) practically at the end point of complete conversion 
into fatty acid and glycerine, and within the cell cause a complete reversal into the 
neutral fat. 
It is certainly true that the concentrations in the solution of the reacting units 
of the chemical system vary the position of the equilibrium point ; but it seems 
highly improbable that any such complete shifting as is required by the above theory 
of hydrolysis in the intestine and re-synthesis in the columnar cell by the same 
enzyme can be attained by changes in concentration alone. 
Such a reversal is, however, possible in the living cell, where there is a supply 
of external energy, and means for its transformation. 
It may be pointed out that such conditions can only very faultily be carried 
out in vitro, and hence it is not surprising that syntheses, such as are undoubtedly 
carried out by the cell in situ, cannot be obtained with the detached cells in test tubes. 
An attempt was made in certain of the experiments recorded below to supply 
such a source of energy by adding dextrose to the solutions, but even then no 
formation of neutral fat could be brought about. 
The oidy action upon the soaps employed, which could be demonstrated with 
certainty, was a considerable conversion into free fatty acid. This result was invariably 
obtained, and is also observable in the experiments of Ewald and Hamburger, 
although little attention is bestowed upon it by these authors. 
The action is, however, of some physiological importance ; in the first place, 
because it is probably the preliminary stage in that synthesis of fit which is 
1. American 'Journal of Physiology, 1902, Vol. vi, p. 331. 
2. Comptes rendus de la Socie'te' de biologic, 1 90 1, p. 70. 
3. This view is also held by Lewkowitsch, Journ. of Soc. of Chemical Industry, Vol. xxii, No. 2, 1903. 
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