n8 SCIENTIFIC FEEDING OF ANIMALS 



been harvested after being attacked by blight, rust, 

 etc. Damage may also have occurred during 

 storage. A few of the ways in which foods may 

 have been reduced in value are — 



1. Admixture of sand, earth, and ashes causes 

 sometimes no injury, even with relatively large 

 amounts, but cases have been met with where 

 violent digestive disturbances, constipation, and 

 death have been the consequence of feeding with 

 food adulterated with the above substances. 



2. The smoke from manufactories, iron works, 

 etc., sometimes carries poisonous metallic sub- 

 stances (arsenic, lead, and zinc compounds) or acid 

 fumes on to the plants. When fodder plants be- 

 come damaged in this way they can cause slow 

 poisoning and wasting of the animal. Fodder 

 attacked by acid fumes may give rise to disease of 

 the bones. 



3. The rust and smut fungi sometimes cause in- 

 flammation and disease of the digestive organs, 

 kidneys and bladder, as well as abortion ; so feeding 

 with materials attacked by these diseases should 

 be avoided as far as possible. By first steaming 

 the diseased fodder and then making it into a kind 

 of silage, it is possible but not certain that the in- 

 jurious properties are removed. The potato disease 

 is held to be non-injurious to health, but it causes 

 loss on account of the decomposition which the 

 tubers undergo. 



