Metastasis. 



i=;i 



emboli, occasions anaemic degeneration of the myocardium; in the 

 brain numerous small hccmorrhages ; and in ^uch or other analogous 

 manner fat embolism may prove fatal. 



Sometimes after traumatic lesions of the tissues, cells are simi- 

 larly swept into the blood, as giant cells from the marrow or liver 

 cells, and lodge in the pulmonary capillaries because of their size. 

 This type of cellular embolism occasions no special disturbance, the 

 occlusive lesion being at the most a minute one and the cells soon 

 broken up or removed by phagocytosis. However, the entrance of 

 tumor cells or pathogenic bacteria into the blood, and the embolic 

 transmission of such bodies, are of much more importance. Their 

 mechanical effects in causing complete or partial occlusion of the 



Fij 



16. 



Fat embolism of the lung, eight days after fracture of the leg. Drawn by 



Dr. Ziesing; X -oO. 



The capillary network of the alveolus to the right is cholved with blood, the 

 lower one with fat and the artery likewise Just above the latter are two 

 air bubbles (showing as dark rings) and several droplets of fat whicn na\e 

 escaped from it (with simple d.irk outline), (.\fter Perls.) 



vessels are of minor significance because of their minute size ; but 

 because of their nature they induce specific changes, the process 

 being knowm as one of malignant embolism or as metastasis (Merdo-rao-ij, 

 displacement ) . We have here to deal with substances which have 

 already given rise to pathological processes in some part of the 

 system, and which are now, by being transported by the blood into 

 new situations in the body, inducing the same disturbances in the 

 latter. Emboli composed of tumor cells originate from autoblas- 



