464 SCIENCE PROGRESS. 



injecting an extract of suprarenal capsules on involuntary 

 muscle is equally marked. The enormous rise of blood 

 pressure which immediately follows the injection is partly 

 due to increase of the heart's force and frequency. This is 

 best seen when the vagi are cut ; if these nerves are in- 

 tact, the heart is slowed ; the increase of arterial pressure 

 is, however, chiefly due to contraction of the arterioles, and 

 this appears to be a direct action of the poison rather than 

 an indirect one through the vaso-motor centre. These 

 facts are supported by very beautiful tracings taken from 

 the heart, from the arteries by the mercurial manometer, 

 and from peripheral organs by the use of plethysmographic 

 instruments. Many of these are reproduced in the paper 

 last cited. 



Szymonowicz and Cybulski confirm these facts in the 

 main. The chief point of difference is that they consider 

 the extract acts upon the vaso-motor centre, and not directly 

 on the blood-vessels. In confirmation of this they state 

 that the action is not obtained after section of the spinal 

 cord. Schafer and Oliver find on the other hand that sec- 

 tion of the cord makes practically no difference. The most 

 important new facts added by Cybulski are contained in 

 the statements that the blood of the suprarenal vein con- 

 tains the active principle of the gland in sufficient amount 

 to produce physiological symptoms, and that the changes 

 in the circulatory and respiratory systems accompanying 

 deprivation of oxygen are no longer obtained in animals 

 which have been deprived a few hours previously of their 

 suprarenals ; they also find that while arterial blood does not 

 destroy the active principle, permanganate of potash does. 1 

 On this fact Cybulski founds a theory that it is got rid of 

 in the body by oxidation. Professor Schafer has carefully 

 tested the statements in reference to asphyxia in three 

 cases and been unable to arrive at the same results ; the 

 absence of asphyxial symptoms observed by Cybulski was 

 probably the result of severe shock. 



1 Moore working in Schafer's laboratory has found that oxidation of 

 an active extract with hydrogen peroxide materially weakens its physio- 

 logical effects. 



