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III. METHODS OF IDENTIFICATION 342 



1. Relative Solubility of Carotin and Xanthophylls 342 



2. Adsorption Properties of Carotin and Xanthophylls . . 344 

 (a) Carotin and Xanthophylls of Green Plants .... 346 



IV. IDENTIFICATION OF BUTTER FAT PIGMENTS 350 



1. Standardization of Absorption Bands 355 



V. CHARACTER OF PIGMENTS IN DIFFERENT BUTTER FATS . . . 356 



1. Light Colored Fats. 2. After Carrot Feeding 357 



3. Colostrum Milk Fat 358 



4. Crystalline Form of Carotin from Butter Fat 359 



VI. RELATION BETWEEN COLOR OF MILK FAT AND FOOD OF Cow 360 



1. Yellow Pigments of Common Cattle Feeds 360 



(a) Cottonseed Meal and Cottonseed Hulls 361 



(b) Bleached Alfalfa Hay 362 



(c) Yellow Corn 362 



(d) The Carrot 362 



2. The Feeding Experiments 364 



VII. RELATION BETWEEN COLOR OF MILK FAT AND BREED OF 



Cow 377 



VIII. DISCUSSION OF RESULTS 383 



IX. SUMMARY 386 



X. BIBLIOGRAPHY 387 



PART III PIGMENTS OF BODY FAT, CORPUS LUTEUM 

 AND SKIN SECRETIONS OF THE COW 



I. INTRODUCTION 391 



II. METHODS OF IDENTIFICATION 392 



III. THE PIGMENTS OF THE BODY FAT 394 



1. Methods of Isolation 395 



2. Identification of Pigments 395 



(a) Experiment I 395 



(b) Experiment II 396 



4 



