250 PHYSIOLOGICAL CHEMISTRY. 



stored np in the fatty tissue, and on partaking of food deficient in 

 fat this accumulation is quickly exhausted. There is perhaps no one 

 of the various tissues that decreases so much in starvation as the 

 fatty tissue. The organism, then, possesses in this tissue a depot 

 where there is stored during proper alimentation a substance of 

 great importance in the development of heat and vital force, which 

 substance, on insufficient nutrition, is given off as may be needed. 

 The fatty tissues, on account of their low conducting power, 

 become of great importance in regulating the loss of heat from the 

 body. They also serve to fill cavities, and as a protection and sup- 

 port to certain internal organs. 



Appendix to the Fatty Tissue. 



Spermaceti. In the living spermaceti or white whale there is found in a 

 large cavity in the skull an oily liquid called spermaceti, which on cooling 

 after death separates into a solid crystalline part, ordinarily called SPERMACETI, 

 and into a liquid, SPERMACETI-OIL. This last is separated by pressure. Sper- 

 maceti is also found in other whales and in certain species of dolphin. 



The purified, solid spermaceti, which is called CETIN, is a mixture of esters 

 of fatty acids. The chief constituent is the cetyl palmitic ester mixed with 

 small quantities of compound ethers of lauric, myrisitic, and stearic acids with 

 radicals of the alcohols, LETHAL, Cj 2 H a6 .OH, METHAL, Ci 4 H 2 9.OH, and 



STETHAL, Ci 8 H 37 .OH. 



Cetin is a snow-white mass shining like mother-of-pearl, crystallizing in 

 plates, brittle, fatty to the touch, and which has a varying melting-point 

 of _|_ 30 to 50 C., depending upon its purity. Cetin is insoluble in water, but 

 dissolves easily in cold ether or volatile and fatty oils. It dissolves in boiling 

 'alcohol, but crystallizes on cooling. It is saponified with difficulty by a solu- 

 tion of caustic potash in water, but with an alcoholic solution it saponifies 

 readily and the above-mentioned alcohols are set free. 



Ethal, or cetyl alcohol, Ci 6 H 33 . OH, which also occurs in the coccygeal 

 gland of ducks and geese (DE JONGE) and in smaller quantities in beeswax, 

 forms white, transparent, odorless, and tasteless crystals which are insoluble 

 in water but dissolve easily in alcohol and ether. ^ Ethal melts at 49.5 C. 



SPERMACETI-OIL yields on saponification valerianic acid, small amounts of 

 solid fatty acids, and PHYSETOLEIC ACID. This acid forms colorless and odor- 

 less, needle-shaped crystals which easily dissolve in alcohol and ether and 

 melt at + 34 C. 



BEESWAX may be treated here as concluding the subject of fats. It con- 

 tains three chief constituents. 1. CEROTIC ACID, C 27 H 6 4O 2 , which occurs as 

 cetyl ether in Chinese wax and as free acid in ordinary wax. It dissolves in 

 boiling alcohol and separates as crystals on cooling. The cooled alcoholic 

 extract of wax contains (2) CEROLEIN, which is probably a mixture of several 

 bodies, and (3) MYRISIN, which forms the chief constituent of that part of 

 wax which is insoluble in warm or cold alcohol. Myrisin consists chiefly of 

 palmitic-acid ether of melissyl (myricyl) alcohol, C e fi.OH. This alcohol 

 is a silky, shining, crystalline body melting at -f 85 C. 



