POISONOUS GLUCOSIDES. 
453 
§ 562.] 
evaporate spontaneously, residues are obtained which will give the 
reactions already detailed. Neither the bromine nor any other chemical 
test is sufficient to identify the digitalins ; it is absolutely necessary to 
have recourse to physiological experiment. The method used by Tardieu 
in the classical Pommerais case may serve as a model, more especially 
the experiments on frogs. Three frogs were properly secured, the hearts 
exposed, and the beats counted. The number of beats was found to be 
fairly equal. Frog No. 1 was placed under such conditions that the heart 
was constantly moist. Frog No. 2 was poisoned by injecting into the 
pleura 6 drops of a solution in which 10 mgrms. of digitalin were dis¬ 
solved in 5 c.c. of water. The third frog was poisoned by a solution 
of the suspected extract. The number of beats per minute was now 
counted at definite intervals of time as follows :— 
TABLE SHOWING THE ACTION OF DIGITALIN ON THE 
FROG’S HEART. 
Frog No. 1. 
Unpoisoned. 
Frog No. 2. 
Poisoned by a known 
quantity of digitalin. 
Frog No. 3. 
Poisoned by the suspected 
extract. 
No. of beats per minute. 
No. of beats per minute. 
No. of beats per minute. 
After 6 minutes, 42 
„ 10 „ 40 
„ 20 „ 40 
,, 28 ■ „ 38 
,, 31 ,, 36 
20 
16 irregular 
15 
0 
0 
26 
24 irregular. 
20 „ 
12 very irregular. 
0 
In operating in this way—which is strictly comparative, and, with 
care, has few sources of error—if the heart of the frog poisoned with 
the unknown extract behaves in the number and irregularity of its 
contractions similarly to the digitalin-poisoned heart, it is a fair in¬ 
ference that, at all events, a “ heart-poison ” has been separated ; but 
it is, of course, open to question whether this is a digitalin or one of the 
numerous groups of glucosides acting in the same way. If sufficient 
quantity has been separated, chemical reactions, especially the bromine 
test (Grandeau’s test), may decide ; but, with the larger number (yearly 
increasing) of substances acting similarly on the heart, great caution in 
giving an opinion will be necessary. 
II.—Other Poisonous Glucosides acting on the Heart. 
§ 562. Several members of these glucosides have been studied by 
Schmiedeberg, 1 and his convenient divisions will be followed here :— 
1 Beitrage zur Kentniss pharmakol. der Gruppe des Digitalins. 
