GENKRAL CONSIDERATION OF DISEASE. 45 



degeneralion, especially parenchymatous and fatty degenera- 

 tions. The most common parenchymatous poisons are the tox- 

 ins, endo-toxins, ptomains, leucomains, phosphorous and silver. 

 3. Hemic poisons. These act principally upon the red blood 

 corpuscles and may inhibit combination of hemoglobin and 

 oxygen, and cause disintegration of the cells and even produce 

 thrombosis. The principal agents that combine with hemo- 

 globin and thereby produce disintegration of the red cells, are 

 carbon monoxide, sulphuretted hydrogen, hydrocyanic acid, the 

 chlorates, and mercury. 



4. Xerve and Cardiac Poisons. These may produce paraly- 

 sis by over-stimulation of nerve centers, or they may produce 

 variation in the rate and force of the heart beat. Narcotics, 

 such as atropine and solanin are types of neurotoxic poisons. 

 Potassium salts depress the rate and increase the force of the 

 heart action. 



A poisonous drug may act in a varietv of ways depending 

 upon the form of the drug, size of dose and method of adminis- 

 tration. 



The following are the more common inorganic poisons: — • 

 arsenic, mercury, sodium, potassium, lead, copper, chlorine, and 

 and the various oxides, salts, acids and bases formed from 

 them. 



]\Iany organic compounds are responsible for poisoning in 

 animals as phenol, iodoform, picric acid, hydrocyanic acid. In 

 fact most of the medicinal organic compounds are poisonous in 

 large doses. 



There are many plants that are responsible for extensive 

 losses of live stock in all parts of the United States, Canada and 

 Mexico, and are most extensive in range districts. Colorado 

 and Montana have had losses aggregating -$200,000.00 annually, 

 in live stock, from plant poisoning. The following table gives 

 the common and botanical names of plants that most frequently 

 produce poisoning in animals. (See insert No. 1.) 



These plants are not all poisonous during their entire 

 development. The cocklebur is most poisonous in the earlier 

 stage of development, that is, at the time the cotyledons come 

 through the soil and for two or three days after the plant is up. 

 Lupines are harmful principally while the seeds are maturing. 

 Larkspurs are harmful only until the flowers appear. Dry sea- 

 sons are usually most favorable to the formation of poison- 

 ous principles in plants. Ergot develops most extensively dur- 

 ing the wet seasons. Second growth or stunted kaffir corn and 



