138 PLANT PRODUCTS 



seeds, the fibre amounts to 18 per cent. Two systems of 

 pressing the cakes have arisen, (i) Where the seed is 

 pressed whole, the husk remains in the cake, and whilst 

 it provides a good channel for the escape of the oil, it acts 

 as an absorbent, and prevents some of the oil flowing out. 

 (2) Where the husk is removed, a lower pressure suffices, 

 but it is not possible to leave the cake with as low a percentage 

 of oil. There are, consequently, many types of cotton cake 

 put upon the market. The Indian cotton cakes derived from 

 seed grown in India and pressed in England usually contain 

 about 4J per cent, of oil, 19 per cent, of albuminoids, and 21 

 per cent, of fibre, and are often dirty and sandy. The short 

 fluff remaining on the seed hinders cleaning previous to 

 pressing. Most Egyptian cotton cakes contain about 5 per 

 cent, of oil, 23 per cent, of albuminoids, and 19 per cent, 

 of fibre, and have a somewhat higher feeding value than 

 Indian cakes. Decorticated cotton cakes are produced 

 in America by removing the husks of the seed previous to 

 pressure. These usually contain 11 per cent, of oil, 40 per 

 cent, of albuminoids, and 8 per cent, of fibre, but great 

 variations occur. Where these cakes are extracted by 

 petroleum spirit the percentage of oil is reduced, and where 

 the decortication is indifferently performed the fibre may 

 rise to 15 per cent. At one time there was a habit of treating 

 Indian cotton cakes with small quantities of borax, for the 

 purpose of preventing fermentation and subsequent dis- 

 coloration. The fashion, however, appears to be dying out. 

 The Soy Bean. — The soy bean is grown very largely 

 in Japan and Manchuria, as well as in other parts of the world. 

 Many crops of soya-bean seeds only contain 16 per cent, of 

 oil. The oil is pressed in the same way as the other oil seeds 

 named above, and the resulting cake contains about 6 per 

 cent, of oil, 42 per cent, of albuminoids, and 5 per cent. 

 of fibre. Soya-bean oil belongs to the drying class of oils, 

 but it is not equal to linseed in this respect. The cake 

 remaining is a particularly palatable one, and much appreci- 

 ated by all cattle. The bean itself is frequently used for 

 human food in the East, and experiments are being made to 



