214 A TEXT-BOOK OF BOTANY. 



in natural fats, and is found in Japan wax. The crystals, formed 

 from the solutions in alcohol or chloroform, are heavier than 

 water. 



Chal'lmoogric acid (CisHo.Oo) occurs as a glyceride in 

 chaulmoogra oil, being obtained from the seeds of Taraktoyenos 

 Kiirzii and other plants of the Bixaceae. It has the composition 

 of linoleic acid, but a study of its constitution shows that it is in 

 the nature of a cyclic compound. 



The following alcohols occur as esters in vegetable waxes : 

 Ceryl alcohol (CosH.^O), combined with palmitic acid, is the 

 principal constituent in opium wax. Ceryl alcohol is also present 

 in carnauba wax, which is obtained from the leaves of the Car- 

 nauba-palm (Copernicia cerifera). Carnauba wax also contains 

 myricyl or melissyl alcohol (CsoHgoO), the latter being either 

 free or combined as an ester of cerotic acid. 



Phytosterol, a compound isomeric with cholesterol 

 (Coyli^gO), is found in the oils derived from a number of seeds. 

 It is unsaponiflable, and is found in the extracted oils to the extent 

 of about I per cent. Phytosterol crystallizes in the monoclinic 

 system (Fig. 117), whereas cholesterol, wliich occurs in most ani- 

 mal oils and fats, forms triclinic plates resembling rhombic prisms 

 (Bomer, Zeits. f. Unter. d. Nahr.- u. Genussmittel, 1898, p. 42). 



Lecithin belongs to a group of fatty substances containing 

 nitrogen and phosphorus, and in which the latter is present as 

 glycerophosphoric acid. They are sometimes grouped together 

 in a special class, known as " phosphatides," and are characterized 

 by containing one or more molecules of phosphoric acid, an alcohol 

 (as glycerin), one or more fatty acid radicals (as stearic or oleic 

 acid), and one or more nitrogenous bodies (such as choline and 

 allied substances). Lecithin occurs in seeds, buds, and young 

 shoots. In barley, wheat, and rye it occurs to the extent of 0.6 per 

 cent. ; in peas, 1.2 per cent. ; lupine seeds, 2 per cent. ; mushrooms, 

 0.9 per cent. ; dry yeast, 2 per cent. (For amount in other plants 

 see Amer. Jour. Pharm., 1914, p. 169.) According to Stoklasa, the 

 phosphoric acid of plants occurs in the form of organic com- 

 pounds, of which lecithin is an important example. It is formed 

 in those organs and under those conditions where photosynthesis 

 is possible. It is even thought that lecithin may be a product 



