298 VETERINAEY STATE BOARD 



the action of silver as a waste producer, the alkalies favor the 

 action of sulphur compounds, both chemically and physiologically. 



What is meant by (a) the physiological action of a drug, (b) the toxic 

 dose of a drug, (c) the lethal dose of a drug? 



(a) The defiiiite and limited action of a drug upon some part of 

 the organism, intended to antagonize or overcome a particular patho- 

 logical condition. 



(b) A dose sufficient to produce poisoning. 



(c) A fatal dose. 



Into what classes are cathartics divided? Name one cathartic of each 

 class and state hovr it acts. 



1. Laxatives : olive oil acts mechanically and slightly stimulates 

 peristalsis. 



2. Simple purgatives : calomel stimulates secretion and peristal- 

 tic action. 



3. Drastic purgatives: croton oil greatly increases peristaltic 

 action and secretions. 



4. Hydragogue purgatives : magnesium sulphate abstracts water 

 from the blood by stimulating secretion. 



5. Cholagogue purgatives: sodium phosphate increases the flow 

 of bile, which stimulates peristalsis. 



How do sedatives act? What is the danger of the excessive use of 

 sedatives ? 

 Sedatives act by depressing protoplasm and lowering functional 

 activity. They allay nervous irritability by diminishing the con- 

 duction of impressions to the brain. Their excessive use may cause 

 the cardiac and respiratory actions to cease. A long-continued use 

 of sedatives may lead to alarming nervous irritability if suddenly 

 discontinued or if the dosage is not increased. 



Give the physiological actions and the therapeutic uses of aconite. 



Aconite decreases the cardiac rate and force, lowers arterial ten- 

 sion and temperature. The respiratory centre is depressed. It is a 

 diaphoretic and diuretic; depresses the functional activity of the 

 perceptive centres in the brain, the sensory side of the spinal cord, 

 and the peripheral sensory nerves. 



It is indicated in all affections characterized by a high resisting 

 pulse and an elevated temperature; is useful in acute pharyngitis, 

 laryngitis, pleurisy, peritonitis, encephalitis, laminitis, enteritis, 

 and mammitis ; also used in acute muscular or articular rheumatism, 

 and as a sedative in cardiac disturbance. 



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