ME. J. PEIESTLEY ON THE PHYSIOLOGICAL ACTION OF VANADIUM. 
555 
7. That when introduced into the system subcutaneously, it does not affect the irri- 
tability of muscle and nerve. 
8. That it depresses the temperature of animals poisoned by it. 
9. That it slows and finally weakens the action of the heart by acting upon its 
intrinsic nervous mechanism. 
10. That it lowers the blood-pressure by acting 
(a) Upon the vasomotor centre. 
(b) Upon the heart. 
11. That it first quickens, then slows, and ultimately arrests the movements of 
respiration by acting on the respiratory centre. 
12. That it causes convulsions and partial paralysis in higher animals, and in 
frogs complete paralysis of voluntary and reflex activity, which is of spinal 
origin. 
In conclusion, the author begs cordially to thank Professor Arthur Gamgee for the 
kindness he has manifested towards him while engaged in this research, and Professor 
Roscoe, for his liberality in supplying and supervising the preparation of the necessary 
reagents. 
Explanation of Plates 45 & 46. 
Figs. 1 & 2 are Tables founded upon Experiments LXXIII.-LXXVII., the results of 
which they present in a comparable form. 
The continuous lines in both figures are curves built upon data obtained from frogs 
poisoned by subcutaneous injection of vanadate of sodium, while the dotted lines are 
curves similarly obtained from frogs injected under the skin with distilled water. The 
method of experiment and the nature of the data are stated on pp. 548-550. (Details of 
Experiment LXXY. were omitted from the text as unnecessary to the comparison at 
that stage. The curve of the experiment is, however, retained here for the sake of 
exactness ; for the experiments of fig. 1 were all under conditions which differed slightly 
from the conditions in the experiments of fig. 2, as may be gathered from the text.) 
In the Tables the time is divided into fractions (minutes), which form abscissae, while 
the ordinates represent the degrees of irritability. The latter are calculated from the 
number of seconds intervening between immersion into the acid and contraction. The 
number 15 was taken arbitrarily as an index of perfect reflex power, indicating instan- 
taneous response to stimulation by the acid. As the number of seconds between immer- 
sion and contraction was found by looking at the second-hand of a watch, without 
any automatic register, all contractions occurring within 1 second of immersion are 
accounted “ instantaneous.” Decline of reflex power was manifested by the successively 
increasing number of seconds intervening between stimulation and response. 
The descent of the dotted curve in fig. 2, after the 140 th minute, is supposititious, 
not ascertained, as reflex power departed during the night (see Exp. LXXVII. p. 550) ; 
but the descent is probably overestimated, i. e. reflex activity declined less rapidly than 
the diagram indicates. 
