4(3 



\i-:tkrinarv patjiology. 



-*.i)i-o-hum plants arc more likely to be injurious than first 

 growth or well developed plants. 



Poisonous plants usually have some noxious properties as 

 odor, taste, or appearance that protects them from consump- 

 tion by animals. Poisoning- usually occurs in animals that are 

 hungry or are not accustomed to the location, or at least are 

 not familiar with the plants that abound there. Animals in 

 districts where poisonous plants are found are usually familiar 

 with the disagreeable properties of them and let them alone or 



Fig. Hi. — Ked Buckeye (AlscuIus Pavlaj 



the animals may become accustomed to the injurious principles 

 of the plant, that is, rle\-elop a tolerance similar to immunity to 

 infecti\-e diseases. 



In their vital activities microphytes (bacteria, veast and 

 moulds) and micmzoa (protozoa) produce chemic sul3stances 

 that are extremely poisonous to animals. Tlius saphro])hytic 

 bacteria produce ])tomains in putrefying flesh. I^ermented, musty 

 or mouldy hay contains injurious substances that produce indi- 

 gestion in tile horse and ox. The specific products of micropara- 



