THE FATS. 



in Fig. 5. For many years it was regarded as a carbohydrate, though an 



exceptional one. It is sweet to the taste, but it gives none of the 



characteristic reactions of sugar. As the chemical constitution of the 



sugars was revealed, it became more and more evident that inosite is 



not a sugar. Its constitution was 



worked out by Maquenne 1 from a 



study of its nitro-substitution and 



other products. It belongs to the 



substances which have a closed 



carbon chain, and its graphic formula 



may be written thus : 



CHOH 



CHOH 



CHOH 



FIG. 5. Inosite crystals. After Frey. 



THE FATS. 



Fat is found in most of the animal tissues. The following table from 

 Gorup-Besanez gives the percentage in the organs and fluids of the body: 



Sweat . . . 0-001 



Vitreous humour . - 002 



Saliva . . . 0'02 



Lymph . . . ' 0'05 



Synovia . . O'OG 



Liquor amnii . O'OG 



Chyle ... 0-2 



Mucus . . . 0'3 



Blood . . . 0-4 



Bile . . . 1-4 



Milk 4-3 



Cartilage 

 Bone . 



Crystalline lens 

 Liver . 

 Muscles 

 Hair . 

 Brain . 



Egg 

 Nerves 



Adipose tissue 

 Marrow 



1-3 

 1*4 



2-0 



2-4 



3-3 



4-2 



8-0 



11-6 



22-1 



82-7 



96-0 



The fats are usually extracted from the finely divided tissue by 

 means of ether in a Soxhlet's apparatus, but in the case of many organs 

 the extraction is incomplete. Dormeyer therefore recommends that 

 the tissue should be subjected to artificial gastric digestion before the 

 extraction with ether ; 2 when this was done, flesh was found to yield an 

 additional - 75 per cent, of fat. 



The fats are compounds of fatty acids with glycerin, and are termed 

 glycerides or glyceric ethers. The fatty acids form a series of acids derived 

 from the monatomic alcohols by oxidation; thus 



From methyl alcohol (CH 3 HO) formic acid (H.COOH) is obtained. 



From ethyl alcohol (C 2 H 5 HO) acetic acid (CH 3 COOH) is obtained, and so on. 



1 Compt. rend. Acad.. d. sc., Paris, 1887, tome civ. pp. 225, 297, 1719, 1853. For colour 

 reactions of inosite, see Scherer, Ann. d. Ohem., Leipzig, 1852, Bd. Ixxxi. S. 375 ; Gaulois, 

 Ztschr. f. anal. Chem., Wiesbaden, 1865, Bd. iv. S. 264 ; Seidel, Bcr. d. deutsch. chcm. 

 Gesellsch., Berlin, 1887, Bd. xx. S. 320. 



* Arch. f. d. ges. PhysioL, Bonn, 1895, Bd. Ixi. S. 341 ; 1896, Bd. Ixv. S. 90; F. N. 

 Schulze (ibid., Bd. Ixv. S. 299 ; 1897, Ixxii. S. 145) has used the same method for the 

 extraction of the fat of blood, and numerous organs. 

 VOL. I. 2 



