SECRETION. 465 



short time followed by death, preceded by some of the symptoms characteristic 

 of Addison's disease. Thus, shortly after their removal the animal becomes 

 tranquil and apathetic; the respiration soon becomes feeble and difficult; 

 prostration supervenes and the animal appears as though paralyzed, but the 

 irritability of the skeletal muscles and nerves is normal; the heart becomes 

 slow, feeble and irregular; the blood-pressure falls promptly 20 to 30 mm. 

 of mercury, after which it steadily falls to a low level; the appetite fails, the 

 temperature declines and death occurs in from twelve to forty-eight hours. 

 In some instances a pigmentation of the skin similar to that seen in Addison's 

 disease has been observed. From the fact that animals so promptly die after 

 extirpation of these bodies, and the further fact that the blood of such 

 animals is toxic to the subjects of recent extirpation, but not to normal 

 animals, the conclusion was drawn that the function of the adrenal bodies 

 is to remove from the blood some toxic product of muscle metabolism. Its 

 accumulation after extirpation was supposed to cause death through auto- 

 intoxication. This view is, however, not generally accepted. 



The Effects of the Injection of Gland Extracts. On the supposition 

 that the adrenals might secrete and pour into the blood a specific material 

 that favorably influences general metabolism, Schafer and Oliver injected 

 hypodermatically glycerin and water extracts of the medulla into the bodies 

 of various animals and observed at once an increased rate of the heart- 

 beats and of the respiratory movements. The effects however were only 

 transitory. When these extracts were injected into the veins directly, there 

 followed in a short time a cessation of the auricular contraction though the 

 ventricular contraction continued vigorously but with a slower rhythm. 

 The blood-pressure at the same time was markedly increased. If the vagi 

 were cut previous to the injection or if the inhibitor influence of the vagi 

 was removed by an injection of atropin the reverse effects were produced, 

 viz., an increase in the rapidity and vigor of both the auricular and ventricular 

 contraction accompanied by a still more marked rise of blood-pressure. This 

 latter effect is the result partly of the increased action of the heart but very 

 largely the result of a vigorous contraction of the muscle-fibers in the walls of the 

 arterioles. This is attributed to a direct stimulation of the arterioles and not 

 to a stimulation of the vasoconstrictor center. The contraction of the 

 arterioles is quite general as shown by plethysmographic studies of the limbs, 

 the spleen, kidney, etc. The arterioles of the lungs and brain do not con- 

 tract under its influence to the same extent as do the arterioles in other 

 regions of the body. Applied locally to the mucous membranes, adrenalin 

 extract produces contraction of the blood-vessels as shown by the pallor 

 which follows. The skeletal muscles are affected by the extract very much as 

 they are by veratrin. The duration of a single contraction is very much 

 prolonged, especially in the phase of relaxation or of decreasing energy. 

 In the foregoing instances the extract apparently produces its effects by 

 an augmentation of the normal tonus of the arteriole muscle. 



It is apparent from these experiments that the adrenal bodies are engaged 

 in elaborating and pouring into the blood a specific material which stimu- 

 lates to increased activity the muscle-fibers of the heart and arteries, and 

 thus assists in maintaining the normal blood-pressure as well as the tonicity 

 of the skeletal muscles. An alkaloidal substance was isolated by Abel from 

 3 



