336 VEGETABLE DRUGS 



sedative eilect upon a weak, rapid, irregular heart, by increasing the in- 

 hibitory and muscular power. Digitalis is indicated: (1) In all condi- 

 tions where the heart is weak, irregular or intermittent, and the circula- 

 tion sluggish; (2) as a diuretic, chiefly in dropsy secondary to cardiac 

 disease, but also in that of renal origin. 



1. In syncope following disease, shock, injury or poisoning (aconite), 

 digitalone is invaluable when injected subcutanecusly together with alco- 

 holic stimulants. Its action is slow, however, and in emergencies it 

 should be reinforced by the use of caffeine or adrenalin. In acute dis- 

 eases, digitalis is one of the most generally serviceable stimulants. The 

 drug is peculiarly applicable in the second stage of pneumonia, because 

 it strengthens the right ventricle, forces the blood through the obstructed 

 lung, and prevents Systemic venous engorgement and arterial anemia. 

 In other words, it equalizes the circulation. Moreover, in stimulating the 

 peripheral vagi, digitalis improves the tone of the bronchioles and pre- 

 vents collapse of the air vesicles, and. by the same action, steadies the 

 rhythm of the breathing. The drug is likewise an efficient circulatory 

 stimulant in influenza of horses and distemper of dogs. Digitalis is 

 frequently prescribed in chronic broncliitis and emphysema, to strengthen 

 the heart and obviate passive pulmonary congestion and cough. Valvular 

 disease of the heart, in its various phases, is the most common field of 

 usefulness for digitalis in human medicine, but in veterinary practice 

 these disorders are rarer and the exact lesion difficult or impossible to 

 diagnose. Also horses with valvular or organic disease of the heart are 

 unsafe and useless for work. In cattle digitalis by the mouth appears 

 to be without action, from probable destruction in the rumen, as the drug 

 is active given intravenously. In mitral stenosis and regurgitation and 

 aortic stenosis, with lack of compensatory hypertrophy of the heart and 

 evidence of circulatory disturbances, digitalis is clearly indicated. In 

 these conditions the drug enables the heart to pump more blood into the 

 arteries and prevents engorgement of the right heart and veins and the 

 occurrence of dropsy. Digitalis cures irregularity of the heart due to 

 auricular 'fibrillation because it either inhibits the fibrillating auricles or 

 the functions of the bundle of His in transmitting the pathological stimuli 

 to the ventricles. Digitalis may be contra-indicated in aortic insuffi- 

 ciency, because in prolonged diastole it allows more time for the blood to 

 flow back from the aorta through the leaky valve into the ventricle. In 

 the second stage of aortic disease wlien the mitral valve is beginning to 

 break dov*n digitalis is decidedly indicated. As a general proposition, 

 digitalis is inferior to aconite in simple cardiac hypertrophy. But thib 

 does not apply when enlargement of the heart is insufficient to compen- 

 sate for valvular lesions. 



Digitalis is extremely successful in palpitation of the heart (horses) 



following over-exertion, but is not appropriate in palpitation due to 



nervousness (dogs), or to indigestion. Digitalis may be exhibited to 



- advantage in rheumatic fever and in endocarditis or pericarditis to quiet 



the heart and secure rest by prolonging diastole. 



2. Digitalis is a valuable diuretic iri dropsy of cardiac origin by 



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