ME. J. PEIESTLEY ON THE PHYSIOLOGICAL ACTION OE VANADIUM. 521 
On Involuntary Muscle. 
Exp. XXXIX.— June 1875. 
Three frogs were taken and decapitated. The hearts of all were exposed, and the 
number of beats in 10 seconds counted. One heart was cut out of the body (including 
the sinus venosus) and placed in a ’5 per cent, solution of NaCl ; another was prepared 
in the same manner, and placed in a solution of sodium vanadate of strength equivalent 
to a ’5 per cent, solution of V 2 0 5 . The third was not cut out of the body, but immersed 
together with the whole upper half of the body in a solution of strength equivalent to 
•05 per cent, solution of V 2 0 5 , the pericardium having been previously cut away. The 
heart immersed in ‘5 percent, solution of the salt of vanadium ceased to beat and failed 
to contract on application of a powerful stimulus (electrical) within 25 minutes of 
immersion; that placed in - 05 per cent, solution within 40 minutes; while the heart 
which was placed in salt solution ceased to beat after 1 hour 45 minutes, and failed to 
respond to stimulation after 2 hours 12 minutes. 
The results of this experiment are similar to those on voluntary muscle ; extremely 
dilute solutions of sodium vanadate quickly cause death of muscular tissue when directly 
applied. 
ii. Special Action of the Poison on the function of Nervous Tissue 
(after local application). 
Exp. XL. — June 1874. 
The legs of a frog were taken, and the sciatic nerve of each divided as high up as 
possible in the abdomen. The thigh was cut away above the knee, leaving the knee- 
joint intact. The nerves were tested, as a preliminary, by means of an interrupted 
current. Each leg moved when the secondary coil was 30 centims. from the primary. 
The arrangement drawn in the following diagram had been previously prepared for the 
reception of each leg : — 
Fig. 1. 
A is a glass capsule containing a *5 per cent, solution of NaCl. 
B is a crucible containing, in the case of one leg, a -5 per cent, solution of NaCl, and in tbe case of the other 
a 2 per cent, solution of V 2 0 6 in the form of sodium vanadate. 
C shows the arrangement of the frog’s limb and the nerve, the purpose of which is evident. 
Helmholtz’s arrangement of the induction-coil (interrupted currents) was used in 
stimulating the nerves from time to time, the minimum stimulus needed to produce 
contraction of muscles being in each case registered. 
mdccclxxvi. 4 c 
