5 o6 TEXT-BOOK OF PHYSIOLOGY 



membranes, disturbance of the digestive functions, indicated by indiges- 

 tion, vomiting and diarrhea; a feeble action of the heart; a small feeble 

 pulse; a low blood-pressure; a subnormal temperature and a shallow 

 respiration. This condition, which is thus largely characterized by a loss 

 of tone in the skeletal as well as the vascular musculature, terminates 

 fatally from a paralysis of the respiratory muscles. Post-mortem exami- 

 nation reveals in all cases a more or less extensive disease of one or both 

 adrenals. A very common lesion is a tubercular degeneration. These 

 symptoms were attributed by Addison to a loss of function of the glands. 



The Effects of Surgical Removal. The removal of these bodies from 

 animals is invariably and in a 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 respira- 

 tion 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 ir- 

 regular; the blood-pressure falls promptly 20 to 30 mm. of mercury, 

 after which it steadily falls to a low level; the appetite fails, the tempera- 

 ture 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 some 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 toxid product of muscle meta- 

 bolism. Its accumulation after extirpation was supposed to cause 

 death through autointoxication. 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. The intravenous injection of adrenal extracts is followed 

 in a very short time by a marked rise in blood-pressure, and if the dosage 

 be large enough, by a cessation of the auricular beat, though the ventricular 

 beat continues, but at a slower rate. If the vagi are cut previous to the 

 injection or if the inhibitor influence of the vagi is removed by an injection 

 of atropin the reverse effects are 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 vaso-constrictor center. The contraction of the arte- 

 rioles 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 if at all, as do the arterioles 

 in other regions of the body, possibly for the reason that the arteriole 



