198 
Transactions of the Royal Society' of South Africa. 
C. GrENERAL AcTION. 
The i^eneral action is seen best when subcutaneous injections of a solution 
of the drug* are given to frogs or mammals. In many cases when it was 
administered by mouth the local action on the gastro-intestinal tract was 
seen, but no other action. The reason of the comparative inability of the 
extract to produce general symptoms in such cases may be : (i) Loss of the 
greater portion in the vomit ; (ii) destruction of the active ingredient by 
the digestive juices ; or (iii) very slow absorption. 
(a) General Action on Frogs, 
About fifty experiments were done, and all gave similar results. The 
following is a typical example : 
Frog, l>Zaia?ia, male, weight 65 grm, 
11 a.m. : 3*25 mgrm. of extract of Urgiuea Burkei dissolved in 0-5 c.c. 
of Ringer's solution injected into anterior lymph-sac of thigh. 
11.5 a.m. : Frog has been jumping about and showing signs of increased 
activity. 
11.15 a.m. : Spontaneous movements have ceased. Frog lies passive, with 
fore limbs extended by side and hind limbs flexed at every joint. 
Able to turn pver if laid on back. Eeflexes greatly diminished. 
11.35 a.m. : No power of movement. Respirations very slow. 
12.5 p.m. : Chest opened. Heart very slow. Auricles beating twice for 
one beat of ventricle. Apex of ventricle pale. 
12.15 p.m. : Heart has ceased to beat. Ventricle pale and contracted ; 
auricles engorged and distended. The gastrocnemius muscle responds 
to direct stimulation and to stimulation of the sciatic nerve. 
Variations. — The diminution of conductivity, resulting in failure of 
alternate impulses to pass from auricle to ventricle, was seen in about one- 
third of the cases. In several experiments the ventricle stopped in diastole 
or only partial systole, but a slight mechanical stimulus applied to the 
ventricle was sufficient to send it into complete systole. 
(b) Dose to ]3roduce Systolic Arrest in One Hour. 
Method. — A tincture was used in which 5 c.c. were equivalent to 1 grm. 
of the bulb. Most of the alcohol was driven off by gentle heat and the 
tincture made up to the original bulk with Ringer's solution. A measured 
amount of this was made up to 0*5 c.c. with Ringer's solution and injected 
into the ventral lymph-sac of a frog. At the end of one hour the frog was 
pithed and the heart examined. 
Results. — Twenty-four experiments with varying doses were made, and it 
was found that the dose required to produce systolic arrest in one hour was 
0 006 c.c. of 20 per cent, tincture per gramme of body-weight of frog. It is 
