ME. J. PEIESTLET ON THE PHYSIOLOGICAL ACTION OE VANADIUM. 535 
Experiment LIII. on a frog, where the usual diminution followed in a heart which was 
directly observed after the removal of all extracardiac nervous influences. 
The rise of blood-pressure which follows injection into the veins of rabbits whose 
cord had been cut is considered to be due to the greater vigour of the heart which 
was noticed. 
IV. SPECIAL ACTION OF THE POISON ON THE FUNCTION OF EESPIEATION. 
The following experiments were performed in order to determine the special action 
of poisoning by vanadium upon the respiratory function. 
In the experiments the depth and frequency of the respirations were recorded upon a 
rotating cylinder, the rate of rotation of which was checked by means of Ludwig’s 
S tromunterbrecher and a magnetic marker, in the manner illustrated by the following 
diagram : — 
Fig. 2. 
A is a large bolt-head, of capacity equal to 16|- litres, stopped by means of an india- 
rubber cork fitted with three glass tubes. One of the glass tubes is connected, by means 
of the caoutchouc tube B, with the glass cannula inserted into the rabbit’s trachea, C. 
Another is connected, by means of the tube D, with a Marey’s tympanum and pen (E), 
arranged so as to write upon a Se Cretan’s cylinder. The third glass tube is connected 
on the one side with a flexible tube descending to the bottom of the bolt-head, and on 
the other with a pair of bellows (F). The object of the pair of bellows is to enable the 
operator to remove completely all traces of respiratory carbonic acid, and thus to avoid 
the fallacies introduced by its presence. 
After every few minutes in the course of an experiment the tube D was occluded at 
d by means of a clip, the tube B was disconnected at b, and the clip at f was removed. 
A few blasts from the bellows then sufficed to thoroughly clear the bolt-head of all the 
products of respiration ; after which the previous conditions were resumed, and the 
