THE KINETIC SYSTEM 



201 



which was clearly manifested in our experiments, 

 leads us to think that the Nissl substance may be a 

 volatile extremely unstable combination of certain 



FIG. 47. BLOOD-PRESSURE TRACINGS CONTRASTING THE EFFECT OF 

 ADRENIN ON THE BLOOD-PRESSURE OF A DOG WHOSE BRAIN ALONE 

 RECEIVED ADRENIN WITH THE BLOOD-PRESSURE OF A DOG WHOSE 

 TRUNK ALONE RECEIVED ADRENIN. 



The blood-pressure, taken from the carotid artery of Dog B, whose brain 

 alone received the stimulus, its body circulation being anastomosed to the 

 brain of Dog A, which received no stimulus, showed a sharp and immediate 

 rise. The blood-pressure of Dog A, whose trunk alone received the stimulus 

 (see schematic drawing, Fig. 46), rose later, but to a lesser degree. The 

 rise in blood-pressure of Dog B is probably due to the fact that adrenin 

 acts directly upon some part of the brain, causing it to send energizing im- 

 pulses to the blood vessels of the body, v/hich result in a rise in blood-pressure. 



An interesting feature of the rise in Dog B was its unusual duration, as 

 compared with the rise in an intact animal given an equal amount of adrenin. 

 The brain-cells of Dog B showed hyperchromatism the inference being 

 that this hyperchromatism is an evidence of increased activity. 



Injection of strychnin causes hyperchromatism of the brain in intact 

 animals ; but injection of strychnin in animals whose adrenals have been 

 removed causes no hyperchromatism in the brain. Injection of strychnin 

 causes an increased output of adrenin. Perhaps the hyperchromatism 

 caused by strychnin is produced indirectly by its mobilization of adrenin. 



elements of the brain-cells and adrenin. The cells 

 of the adrenals do not take the Nissl stain, and the 



