FOE, CERTAIN ORGANIC POISONS. 
423 
3. The characteristic effect of each of these agents on frogs is the production of irre¬ 
gularity of the heart’s action, followed by complete stoppage of its pulsations; the ven¬ 
tricle remaining rigidly contracted, and perfectly pale, after it has ceased to beat; the 
muscular power of the animal being at this time unimpaired, and persisting as long as in 
frogs in which the circulation has been stopped by other means, such as ligature of the 
heart 
The irregularity in the heart’s action, which precedes its stoppage under the influence 
of these poisons, is peculiar. The rhythm is but little altered; and the beats are not 
necessarily diminished in number, as has been supposed. Sometimes, however, the ven¬ 
tricle makes only one pulsation for two of the auricles, the number of its contractions 
hein 0- therefore lessened by One-half. More frequently the irregularity consists in one or 
more portions of the ventricle (especially the apex) becoming rigidly white and con¬ 
tracted, while the remainder of the organ continues to dilate regularly. When the 
yielding portions arc small, a peculiar appearance, as if the wall of the ventricle fonned 
crimson pouches or protrusions, is produced.. 
4. No other substance, except those mentioned above, has been found to produce this 
chain of effects, even in a single experiment. We have ourselves tried nineteen different 
substances, consisting of vegetable extracts and alkaloids. Of these, emetma , and the ex¬ 
tract of the Delphinium Staphysagria caused somewhat similar irregularity of the cardiac 
beats; but in frogs, poisoned by these agents, the muscular power was always lost be¬ 
fore the heart had ceased to beat, and the ventricle stopped m the dilated, and not in 
the contracted state. . „ , 
5. When digitaline is applied endermically to frogs, the characteristic effect is in¬ 
variably produced, if a sufficient quantity be used. This quantity no doubt varies with 
the size of the animal, but may be stated generally at -^t'h of a gram. Quantities less 
than 1 th grain usually produce no effect, or at most only temporary irregularity of the 
heart’s action, of a more or less characteristic kind. The results of the injection of doses 
larger than _A_th grain is to diminish the interval between the administration of the 
poison and thestoppage of the ventricular beats. This interval appears to be seldom 
less than six or seven minutes, however large the quantity of uigitalme. 
6. Very poisonous effects are produced in frogs by the endermic application of alco¬ 
holic or acetic extracts of matters vomited by patients, or taken from the human stomach 
after death. The extracts are less poisonous, if at all, to the higher animals. 
7 The symptoms produced by these extracts in frogs are m marked contrast to those 
caused by the cardiac poisons. Like these agents, the animal extracts impair the action 
of the heart; but their tendency is to cause paralysis of its muscle, and stoppage m the 
dilated condition. At the same time, they generally destroy the muscular power Oi the 
8 The cause of the toxic action of these animal extracts has not been ascertained; it 
is probably not always the same, as the effects produced by different extracts are not 
perfectly similar. These effects are perhaps the result oi the combined action of dif¬ 
ferent substances.' They are certainly not caused by bile or pepsme, and probably not 
by any substance in a state of decay. . ,, r 
9. The vegetable acids, when injected in sufficient quantity, stop the action of the 
heart more rapidly than any poison with which we are acquainted, the organ remaining 
distended with blood when it has ceased to beat. The toxic action of the animal ex¬ 
tracts is net, however, caused by these acids; for the quantity of hem contained in 
the extracts is too small, and the effect is not diminished oy neutralization with an 
alk lo!‘ When digitaline, in quantities of f-i grain, is added to vomited matters, or to 
fluids taken from the human stomach post mortem , the extracts obtained from such 
fluids almost invariably produce on frogs the effects of digits one. 
11 This is due partly to the fact that the action of digitaline is generally more rapid 
than'that of the poisonous constituents of the extracts themselves but principally to the 
circumstance that it was necessary to give only small doses of the extracts coma m 0 
digitaline, in order to get the characteristic action. ., ,. t i , 
12. The method of dialysis fails in many cases to separate digitaline from complex 
organic mixtures which contain it; and this method is rarely of service m aiding le 
detection of this poison by the physiological test.. • . 
13. When digitaline was administered to dogs m quantities little more than sufficient 
