476 Prof. J. T. Cash and Dr. W. R. Dunstan. [May 24, 
0:0009.—Considerable excitement with irregularity of reflexes in limbs 
and inability to assume ventral position when placed on dorsum. The 
lungs are in the main widely inflated; respiratory movements occasional. 
0:0012.—After initial excitement with frothing there is slowing and 
suspension of respiration—gaping. Reflexes much impaired and very 
uncertain. Prolonged inability to get off dorsum. Recovery not complete 
for five days. 
0:0013.—This is a hyperlethal proportion. After excitement there is rapid 
failure of voluntary movement. Reflexes are diminished and uncertain in 
half an hour after injection. Respiration, after brief acceleration, is slowed 
and abolished. Heart’s action becomes incoordinate. If death occurs 
(from cardiac failure) in five to six hours, some reflex may occasionally be 
elicited even when circulation has ceased, but if the lethal issue is post- 
poned till some hours later, the limb reflexes disappear first, the body being 
limp and flaccid. The ventricle shows characteristic sacculations containing 
blood. The gastrocnemius is excitable to direct stimulation, usually the 
response to indirect stimulation is impaired. 
The lethal dose of indaconitine varies in different seasons of the year. 
For R. temporaria in June and July a proportion of 0°00120 gramme per 
kilogramme was lethal on several occasions, and the proportion of 0:00125, 
which may be regarded as the lethal, was only twice exceeded (00014 and 
0:00145) with subsequent recovery. 
Action of Indacomtine upon the Cardiac Rhythm.—Lethal and slightly 
hyperlethal doses of indaconitine cause acceleration of the heart of brainless 
frogs, amounting to from four to eight beats per minute. The acceleration 
may be progressive after injection, or may be preceded by slight slowing (two 
to three per minute). After a duration, which varies largely according to the 
dose, acceleration passes into irregular rhythm with incoordinate action, 
the ventricle being chiefly affected. It is after this condition has lasted for 
a time that the characteristic “ pouching” of the ventricle is produced by 
indaconitine, as it is by all the aconitines hitherto examined in this research. 
Subsequently, after lethal doses, a progressive slowing and enfeeblement of 
the ventricular beat occurs, until spontaneous action ceases. At this time 
the auricles are beating with some degree of regularity at a rate of 10 to 16 
per minute. Local application of atropine restores spontaneous contraction 
of the ventricle to some extent. 
Perfusion of Frog's Heart—The main results of the perfusion of the 
separated ventricle by weak doses of indaconitine, are to increase excitability, 
accelerate the rhythm, and favour the occurrence of group beating. Large 
doses—0°0004 to 0:0006—produce rapid deterioration in the strength and 
