104 VETERINARY MATERIA MEDICA. 



Physiological Action.— Convallaria is a very- 

 valuable heart tonic, diminishing the frequency and 

 increasing the strength of the heart beat, raises arte- 

 rial tension, slows and deepens the respirations, and 

 increases the amount of urine excreted. Unlike digi- 

 taUs, it has no cumulative action, but very closely re- 

 sembles that drug in its action as a cardiac tonic and 

 as a diuretic. In over-doses it is an active poison, 

 causing irregular cardiac action, gastro-enteritis, rap- 

 id feeble pulse, and greatly lowered blood pressure, 

 slowed and labored respirations, and finally heart 

 arrest in systole, by direct stimulation of its inhibi- 

 tory apparatus. 



Therapeutics. — Convallaria is considered safer 

 than digitalis, and may be employed in all cases 

 where the latter drug is indicated. In cardiac neu- 

 rosis it frequently gives prompt relief when digitalis 

 has failed. 



Belladonna— Deadly ISTightshade. 



The leaves and root of Atropa belladonna, a Euro- 

 pean plant, natural order Solanacese, and containing 

 two alkaloids. The more important of these, atro- 

 pine, the active principle, is in general use ; while the 

 other, known as belladonnine, is but seldom used for 

 its therapeutic properties. The plant contains also 

 malic acid and a coloring matter known as atrosin. 



Derivatives of Atropine. — Atropine may be re- 

 solved into tropin and tropic acid, both of which, as 

 well as atropine, may be produced synthetically. 

 Homatropine is the product resulting from treating 



