X CONTENTS 



II. The Digestion and Absorption of Fats in the Gastrointestinal Tract 



(continued) 



(2) Changes in Fat in the Intestinal Cells 157 



a. The Breakdown of the Fatty Acid + Bile Salt Complex in the In- 



testinal Cells 158 



b. The Synthesis of Phospholipids in the Intestinal Mucosa 158 



(a) Phospholipids as Obligatory Components in Fat Synthesis. . . 160 



(b) Functions of Phospholipids Other Than in Fat Synthesis. . . . 161 



c. The Synthesis of Fats 162 



(3) The Transfer of Fat to the Interior of the Villi 164 



a. Introduction 164 



b. Theories for the Mechanism of Transfer 164 



(a) Theory of Schafer 164 



(b) Theory of Heidenhain 164 



(c) Hydrolysis-Resynthesis Theory of Loevenhart 165 



(4) The Transport of Fat to the Liver and Tissues 165 



a. The Transport of Fat in the Lymph 165 



(a) The Comparative Composition of Ingested and Lymph Fat. 167 



b. The Transport of Fat in the Portal Circulation 168 



c. The Route of Distribution of Fats vs. Fatty Acids 170 



(5) Current Status of Theories of Fat Absorption 172 



8. The Rate of Absorption of Common Fats 172 



9. Factors Affecting the Rate of Absorption of Fats 178 



(1) Age and Sex. . . .' 178 



(2) The Nature of the Fat 180 



a. The Rate of Absorption of Synthetic Simple Triglycerides 180 



b. The Rate of Absorption of Fatty Acids 181 



c. The Absorption of Short-Chain Acids 181 



d. The Effect of the Melting Point of the Fat 184 



(3) The Presence of Emulsifying Agents 185 



a. The Effect of Lecithin on the Absorption of Fat 185 



b. The Effect of Diglycerides and Monoglycerides on the Absorption 



of Fat ..." 188 



c. The Effect of Isopropyl and Stearyl Citrates on the Absorption of 



Fat 188 



d. The Effect of Polyoxyethylene Sorbitan Monooleate (PSM) on 



the Absorption of Fat 188 



(4) The Role of Adrenocortical Hormones 189 



(5) The Effect of Inhibitors on Fat Absorption 191 



a. Monoiodoacetic Acid 191 



b. Phlorhizin 192 



(6) Miscellaneous Factors Affecting Fat Absorption 193 



III. The Digestibility of Fats 195 



1. Introduction . . 195 



2. Methods for the Study of Digestibility of Lipids 196 



(1) Procedure of Atwater Used in U.S.D.A. Studies 196 



a. Correction for Metabolic Fat or Metabolic Lipid 197 



