CONTENTS XXXI 11 



\ni. The I*hysiolog;y and Biochemistry of the Essential Fatty Acids 

 (ran tin tied) 



(3) Chemical and Physical Methods for the Analysis of Polyunsatu- 



rated Acids 790 



a. Thiocyanogen Number 790 



h. Solubility of Bromide Derivatives 791 



c. Spectrophotometric Determination 791 



d. Resume of Methods for the Analysis of Polyunsaturated Acids 792 



(4) Sj'nthesis of Polyunsaturated Acids 793 



3. Bioassay of Essential Fatty Acids 794 



(1) Growth Method of Greenberg and Co-Workers 794 



(2) Growth Method of Thomasson Based upon Rationing of Water. . 795 



4. Comparative Biopotencies of the Essential Fatty Acids 796 



( 1 ) Introduction 79G 



(2) Proof of the Inability of Animals to Effect a Biosynthesis of the 



Poljnmsaturated Acids 796 



(3) The Question of the Possible Biopotency of Oleic Acid and of 



Other Monoethenoid Acids 797 



(4) The Biopotency of Linolenic Acid vs. Linoleic Acid 798 



(5) The Biopotency of Arachidonic Acid vs. Linoleic Acid 799 



(6) The Biologic Activity of Related Compounds 800 



5. Factors Affecting the Requirement for Essential Fatty Acids 801 



(1) The Effect of Species 801 



(2) The Effect of Sex 804 



(3) The Effect of Substances Fed Concomitantly 805 



a. Fatty Acids 805 



b. Mineral Oil 806 



(4) The Effects of Vitamins and Hormones 807 



6. Interconversions of the Polyunsaturated Fatty Acids 809 



( 1 ) Interconversions of Linoleic Acid 809 



a. Conversion to Arachidonic Acid 809 



(a) Experimental Evidence of the Reaction 809 



(b) Mechanism of the Conversion 81 1 



b. Conversion to Polyunsaturated Acids Other Than Tetraenoic 



Acid 813 



(2) Interconversions of Linolenic Acid 813 



a. Factors Altering the Trienoic Acid Content of Tissues 813 



b. Transformations of Administered Linolenate 814 



(3) Interconversions of Elaeostearic Acid 815 



(4) Interconversions of the More Highly Unsaturated Acids 815 



7. Physiologic Functions Related to the Essential Fatty Acids 816 



(1) Growth 816 



(2) Normal Skin Development 819 



(3) Pregnancy and Lactation 820 



(4) Protection against X-Irradiation 822 



(5) Relation to Capillary Fragility 823 



(6) Relation to Cholesterol Metabolism 824 



