THE DUCTLESS GLANDS. INTERNAL SECRETIONS. 193 



in the circulation the dissolution of numerous leukocytes, from whose disintegration 

 the fibrin-factors result. It is curious that hemoglobin exposed to the air gradually 

 loses this property; also fibrin-ferment in contact with hemoglobin is gradually 

 destroyed or rendered inactive. 



As numerous small vessels are occluded as a result of the processes described, the 

 signs of impeded circulation and of stasis will be encountered in the different organs 

 of the body. In man, the injection of lamb's blood is followed by a bluish-red dis- 

 coloration of the skin. The obstacles encountered by the blood-current in the lungs 

 cause dyspnea or even laceration of the small vessels in the air-passages and bloody 

 expectoration. The dyspnea may increase if interference with the free circulation 

 of the blood develops at the respiratory center. The digestive organs, for the same 

 reason, exhibit increased intestinal peristalsis, diarrhea, evacuation of the bowels, 

 tenesmus, vomiting and abdominal pain. These phenomena are explained by the 

 fact that any disturbance of the circulation in the abdominal vessels is followed by 

 increased peristaltic movements. In the kidneys secondary degeneration of the 

 glandular substance takes place in consequence of occlusion of the vessels. The 

 uriniferous tubules are occluded by casts consisting of coagulated albuminous 

 material. In the muscles the occlusion of numerous vessels may 'cause stiffness, 

 or even rigidity from coagulation of myosin, just as in Stenson's experiment, 

 together with increased heat-production. Also the nervous system, the organs 

 of special sense and the heart may exhibit various disturbances, all of which can 

 be attributed to the occlusion of vessels and the resulting interference with the 

 circulation. It is interesting to note that the transfusion of foreign blood is 

 followed as a rule within half an hour by the development of active fever. Finally, 

 it should be mentioned that lacerations of the vessel-walls have also been observed. 

 These explain the obstinate hemorrhages that may occur not only on the free 

 surfaces of mucous and serous membranes, but also in the parenchyma of organs, 

 as well as in surgical wounds. The blood itself coagulates slowly and imperfectly. 

 By far most of the facts bearing on the transfusion of heterogeneous blood that 

 have been mentioned were discovered through Landois' investigations. 



Attempts to inject other substances instead of blood are not to be commended: 

 from 0.75 per cent, to 0.9 per cent, saline solution, while capable of improving 

 the circulatory conditions in a purely mechanical way, and thus exerting a favora- 

 ble influence, is obviously incapable of supporting life in cases of severe anemia, 

 in which the quantity of blood remaining in the body is insufficient to maintain 

 the vital processes. 



THE DUCTLESS GLANDS. INTERNAL SECRETIONS. 



Within comparatively recent times there has been attributed to the 

 ductless glands, whose activity is still, for the most part, shrouded in 

 obscurity, a special and important function, namely, the production of 

 substances that enter the circulation and there in some peculiar way 

 excite certain activities, or render innocuous certain poisonous sub- 

 stances generated in the process of metabolism, either by destroying 

 these or by manufacturing an antidote. In a similar manner it has been 

 asserted of a number of other organs in the body that, in addition to 

 their special function, they exert an important influence on the economy- 

 by means of such internal secretion. Thus, Brown-Se"quard and d'Ar- 

 sonval asserted that the kidneys are in part concerned in rendering 

 innocuous the toxic substances that accumulate in the body after 

 nephrectomy; Tigerstedt and Bergman, that the kidneys produce a 

 substance renin that increases the blood-pressure and has a powerful 

 influence on the peripheral nerve-centers. The substances under 

 consideration can be obtained from the corresponding organs in the 

 form of extracts and their action can then be tested upon the animal 

 body. 



The spleen is contained in a firm fibrous capsule, which at the hilus gives off 

 an investment for the entering blood-vessels. From the inner surface of the cap- 

 13 



