VEGETABLE FOODS. 183 



when not worked. This residue can only be given when in a perfectly 

 fresh condition, or when well preserved. 



The residue after the extraction of oil from the seeds of the 

 various members of the cotton-plants (Gossypium herbaceum), or so- 

 called cotton-seed cake, furnishes a valuable food for fattening and milk 

 cattle. The seeds are inclosed in a capsule, which bursts as the fruit 

 ripens, and which are covered by white fibres which form the so-called 

 cotton. After the removal of the cotton, the seeds, which have a hard 

 shell, contain an oily, greenish-white nucleus, from which the oil is 

 removed by pressure. The residue from this process of extraction of 

 the oil is by no means constant in its composition, and is therefore not 

 always suitable for a food. For example, many of the cotton-seed 

 cakes contain both parts of the indigestible hull of the seed and con- 

 siderable cotton, and are therefore only suitable for manures. When 

 such an article is given to cattle serious disturbance of digestion is pro- 

 duced, and may even prove fatal from obstruction and inflammation of the 

 alimentary canal. In England the cake produced from the Eg3 T ptian 

 seeds forms a favorite article of fodder. The most nutritious and most 

 readily digestible are the cakes from the hulled seeds. The following- 

 table gives their composition : 



The oil-cake from the hulled seeds constitutes one of the most 

 nutritious of all fodders. From digestion experiments on ruminants 

 Wolff has found the following amounts to be digested: 



Protpuls T^ata Non-nitrogenous 



Fats ' Extractive Matters. 



Hulled cakes, 84.7 87.6 95.1 



Unhulled cakes, .... 73.4 90.8 46.2 



The higher digestibility of the oil-cake from the hulled seeds is with- 

 out doubt to be attributed to the large amount of cellulose in the hulls. 

 The oil-cake from the unhulled seeds is of a dark-brown color, while that 

 from the hulled seeds when fresh is greenish, but also becomes brownish 

 with age. Both of these forms of fodder are often contaminated by the 

 accidental mixture of various substances, such as particles of iron from 

 the presses, and when kept in moist places with various forms of moulds 

 which lead to the development of ptomaines and other poisonous alka- 

 loids, and so may explain their hurtful action. The American cotton-seed 



