54 Proceedings of the Royal Society 
as sulphuric acid, will show everywhere a marked diminution, as 
measured by the metronome, in the diastaltic activity; while a 
slight touch of the skin in the poisoned region, which before the 
administration of the poison caused no effect, will now produce 
faint twitches of the limb whose vessels are tied. 
6. A frog may have its cardiac contractions reduced from seventy 
to eight or ten per minute , its respiratory movements completely 
stopped , and the endorgans of its motor nerves paralysed , by a still 
smaller dose , and afterwards completely recover. This has occurred 
when two grains were injected into the abdominal cavity of a frog 
weighing seven hundred and thirty grains. 
7. In frogs, the voluntary muscles are unaffected by the poison, 
and may continue to respond to galvanic stimulation during three 
or four days after its administration. The contrast and indepen- 
dence in the effects of Calabar bean on the motor nerves and on 
the muscles may be well shown by ligaturing the ischiadic vessels 
of one limb before injecting the poison. If, when strong stimu- 
lation causes no reflex movement, the two gastrocnemii muscles 
with their attached nerves are so placed that an interrupted cur- 
rent, from one Daniell’s cell and Du Bois Eeymond’s induction 
apparatus, may be transmitted simultaneously, either through both 
muscles, or both nerve-trunks, it will be found, in the case of the 
muscles, that when the secondary coil is slowly advanced, contrac- 
tions will occur with the same current in both muscles, or with a 
weaker current in the case of the poisoned than of the non-poisoned 
muscle, this varying with the length of time which has elapsed 
since the limb was deprived of blood ; when the current is trans- 
mitted through both nerves, contractions will be simultaneously 
produced, or with a weaker current in the non-poisoned, or contrac- 
tions will occur in the non-poisoned muscle only, this varying with 
the length of time which has elapsed since the exhibition of the 
poison. 
8. In mammals and in birds the voluntary muscles are affected 
in a very remarkable manner. At an early stage of the poisoning 
faint twitches occur, which gradually extend over the body, and, 
at the same time, increase in vigour, so as to interfere with the 
respiratory movements. Shortly before death, they again become 
mere successive twitches, often requiring the hand to be placed 
