GROSSER PATHOLOGICO-ANATOMICAL LESIONS 207 



blood serum so that when it was injected into animals one of whose adrenals 

 had been excised death was produced or hastened. From the sum of these 

 investigations the observers conclude that, after the operation, substances cir- 

 culate in the blood which under normal circumstances are rendered harmless 

 by the adrenals ; that the latter are therefore protective organs in relation to 

 certain toxic products of metabolism. Further consideration caused a number 

 of these observers to emphasize the similarity of the symptoms to those of 

 curare poisoning. This was true of the animals operated upon as well as 

 those animals into whom the blood was injected (particularly in regard to 

 the action upon the nerves). It was also determined that after inoculation 

 of the blood and serum of dogs into other animals whose muscles were ex- 

 hausted by tetanizing action was produced similar to that after the removal 

 of the adrenals. Eegarding the substances which appear to be neutralized 

 by the normal function of the adrenals, these experiments Justify us in believ- 

 ing that they are the toxic products of the metabolism of muscular activity. 



Finally I must mention the researches of Jacobi, which appear to prove 

 an intimate relation between the adrenals and intestinal peristalsis. And this 

 influence must be looked upon as an inhibitive action exerted on the gut by 

 the adrenals. Extirpation of the adrenals acted like division of the splanchnic 

 and produced active intestinal peristalsis while irritation of the adrenals caused 

 the intestine to remain quiescent. The adrenals accordingly are looked upon 

 as branches of the splanchnic, and the inhibitive tracts controlling the intes- 

 tine considered to be fibers which lead from the adrenals to the semilunar 

 ganglions. It is true these investigations have not as yet been thoroughly 

 confirmed. 



In the reports of experiments up to the present time, therefore, certain 

 points of support are found for ascribing to the adrenals an important func- 

 tion in the organism. 



This conviction is strengthened and confirmed by other recent investiga- 

 tions, in which the attempt was made to introduce the active constituents of 

 the adrenals in the form of an organic extract (watery, glycerin-containing, 

 etc.) into animals by injection, and to study the action thus produced. I 

 shall only mention a few of the most important, and the conclusions which 

 have been drawn from them regarding the function of the adrenals: 



After a few earlier observers had determined the toxicity of adrenal 

 extracts, noting the effect of injections in difEerent animals who showed 

 symptoms of general body and nervous weakness, Oliver and Schafer (1894 

 and 1895) were the first to make minute studies regarding this condition. 

 They found as the most conspicuous action of intravenous injections of the 

 extract (particularly that obtained from the medullary substance) a transitory 

 but very decided rise of blood-pressure. Further investigations (cutting the 

 vagus, injection of atropin, destruction of the medulla oblongata and of the 

 spinal cord, etc.) proved that this rise in blood-pressure is due to a direct 

 increase of vascular tonus and general muscle- tone (particularly in the heart 

 and in the vessels). The extract, besides strengthening the cardiac action, 

 also slows it. Adrenal extracts which were taken from cases of Addison's 

 disease were inactive. The observers conclude: That the adrenals secrete a 



