The poisonous plants treated of in this chapter belong to the Monoco- 

 tyledoneae. Botanically the class is distinguished, as follows: The 

 permanent roots are secondary being produced adventitiously, or at the 

 time of embryonic development. The sap bundles in the stem are scattered 

 and are closed, that is, each one is surrounded with a bundle sheath of 

 sclerenchyma, which prevents further enlargement of the bundle. The 

 principal veins of the leaves are parallel. The floral symmetry is of the 

 trimerous kind and the embryo, usually surrounded with reserve food, 

 possesses only one seed leaf, or cotyledon. 



Fodder or Silage Poisoning. Two grasses are considered responsible 

 for poisoning when fed as dry fodder or silage. These grasses are maize, 

 or Indian corn (Zea Mays) and sorghum (A ndropogon Sorghum). The 

 author is not aware that any profound investigation has been made of the 

 exact conditions under which poisoning is to be attributed to cattle eating 

 fodder, or silage. Two alternatives seem to be possible. Corn stalks 

 and the stems of sorghum are not easily digestible and the impaction of 

 their fibers in the digestive tract may bring on severe cases of indigestion, 

 especially where the cattle do not have access to plenty of water. The 

 other alternative is in the poisonous action of toxic substances developed 

 in the stored maize, or sorghum. It is known, that when corn silage is 

 not properly stored, that is, where air has free access to all parts of the 

 silage, that prussic acid develops. A glucoside occurs in the maize stem 

 and this is capable of being converted into hydrocyanic acid, HCN, by an 

 enzyme in the plant. After periods of extreme drought in the case of 

 sorghum, the leaves of the plant contain considerable quantities of hydro- 

 cyanic acid. This acid is an extremely toxic substance being the most 

 rapidly acting drug we possess. Lethal amounts paralyze the respira- 

 tory center and the heart muscles, death, as a rule, being due to failure of 

 respiration with almost simultaneous cessation of the action of the heart. 



Twenty-one head of cattle, out of a total number of 32 animals, were 

 poisoned at Aurora, Colorado on August 3, 1901 by eating Kaffir corn, a 



45 



