DIGITALIS. 
757 
is produced by increasing the contractions, causing the cavities 
to get smaller and smaller, and preventing the diastole or re¬ 
laxation of the eavities. 
Stoppage of the heart’s action is due, not to paralysis, but to 
spasm which occurs during the systole. 
In poisoning, tannie acid is the antidote, while aeonite is 
the best antagonistie when large doses have been given. Opium 
is useful when digitalis has been used for a long time, as the 
former produees relaxation of the heart. 
From the foregoing we find the indications for the use of 
digitalis made clear ; when the heart is weak and only when 
the work required of that organ is less than the power to per¬ 
form the same, digitalis is iLseful. 
The drug can be given in dilated heart due to the relaxa¬ 
tion of the muscles of that organ beyond their normal. In these 
cases the contractile power is lacking or weak, and the walls of 
the heart are unable to expel its contents owing to its relaxa¬ 
tion. Digitalis here causes the necessary contraction and aids 
in emptying the cavities. The drug is eontra-indicated in fatty 
heart and usually in cardiac hypertrophy, except possibly when 
associated with dilatation. 
In dropsy when it is due to or associated with an interfer¬ 
ence in the action of the kidneys, digitalis is good as it is elimi¬ 
nated by the kidneys, and hence its diuretic qualities. 
In pneumonia the danger we anticipate and encounter is a 
weak heart, and not as a rule a dilated heart, and in these cases 
digitalis is of no use. In this disease it may be indicated about 
the time of crisis, at which time the heart cannot drive the 
blood through the lungs, owing to the weakness of the walls of 
the right side of the heart, together with the obstruction in the 
lungs. Digitalis should not be given in this disease when the 
fever is high, as the heart is not dilated at this time (although it 
may be weak), but the organ relaxes when the fever suddenly 
falls, and hence in these cases digitalis does good. I speak of 
this because I think the use of digitalis has been, and is, abused 
in these cases, as it is used as a routine remedy. 
