96 THE CHEMISTRY OF CATTLE FEEDING 



is liable to set up inflammation in the stomach and bowels of 

 animals, and feeding stuffs which contain mustard seeds (p. 

 274) are regarded as injurious. 



Vegetable Acids. The juices of fruits, the stems and 

 leaves of most herbaceous plants, and several cultivated roots, 

 are generally more or less acid to test-paper. In certain cases, 

 especially in the unripe condition, they are strongly acid. 

 This condition is due to the presence of acid potassium and 

 calcium salts, of dibasic and free monobasic carboxyllic acids. 

 Neutral salts of the same acids are usually present in con- 

 siderable quantity in the less acid or neutral plant juices. A 

 slightly acid condition of the food appears to be agreeable to 

 the taste of many of the herbivorous animals, and is probably 

 favourable to the processes of digestion. 



The acids may be classified according to the ordinary rules 

 of organic chemistry. A few examples are given below. 



(1) Monobasic Fatty Acids ; CH 2n O 2 . Acetic acid, C 2 H 4 O 2 , 

 which may be taken as the type of this group, is perhaps the 

 most widely distributed of all the vegetable acids. It is 

 present either in the free state or as a salt in the juices "of 

 nearly all common plants. It is formed in seeds during the 

 process of germination, and in nearly all fermentations of 

 vegetable matter. It is, therefore, found, sometimes in con- 

 siderable quantity, in brown hay and silage products. 



(2) Hydroxymonobasic Acids. Glycollic acid, or oxyacetic 

 acid, CH 2 (OH).COOH, is found in unripe grapes, in the 

 leaves of wild vine, and many other plants. Like all such 

 acids it has a pleasant ethereal taste. 



(3) Dibasic Acids. Oxalic acid, (COOH) 2 , is probably the 

 commonest member of this group. Considerable quantities of 

 the potassium hydrogen salt are obtained from several varieties 

 of sorrel and rumex. The free acid occurs in boletus, and the 

 acid calcium salt occurs in rhubarb, to which it imparts a 

 characteristic, rather unpleasant, earthy taste. The neutral 

 calcium salt is found in clovers, and most other leguminous 

 plants. The acid and its salts are regarded as deleterious, 

 and, in larger quantity, even poisonous to animals. Malonic 

 acid, CH 2 (COOH) 2 , occurs in beetroot. Succinic acid, 



