' 



270 THE BLOOD AND THE LYMPH 



the platelets may be seen. In other respects the supposition is strongly 

 corroborated, and altogether it appears that the origin of the thrombo- 

 cytes is now fairly well established. 



Fine granules are to be seen in these corpuscles and indeed these form 

 a conspicuous part of the platelet. The problem as to the meaning of 

 these granules is an interesting one. What have they to do with coagu- 

 lation ? Is it possible that they represent a granular nucleus ? 



Because of .their very rapid disintegration when blood is shed and of 

 -iheir abundant adherence to threads, etc., suspended in blood, it has long 

 been suspected that the platelets were concerned in coagulation. Burker 

 has now shown indeed that this process is dependent on their destruction 

 or solution, as was described on page 260, and Ducceschi has corroborated 

 part of this result. What other use they may have, if any, is unsuspected 

 as yet. 



FIG. 142 





Highly magnified view in the spleen of a salamander: g, capillary; z, pulp; 

 Ic, lc', leukocytes; rk, erythrocytes. (B. Haller.) 



Besides these three sorts of relatively substantial structures floating in 

 the blood, H. F. Muller discovered that there is another sort which he calls 

 hemoconia or blood-atoms. They are much smaller than the platelets 

 even. His claims have now been generally substantiated and it is an 

 almost natural probability that the debris of the various corpuscles should 

 persist a time in the blood. In particular the granules of the eosino- 

 philic leukocytes have been thought of. What, if any, their function is 

 no one as yet knows. 



Lymph. For the causes of the movement of the lymph see the next 

 chapter; its chemical composition has already been given (page 256). 

 Internal nutrition, the mutual interchanges between the tissues and the 

 circulating blood, denotes in a single expression the function of the 

 lymph. Lymph is in nearly all respects and all over the body the inter- 

 mediary between the blood (the agent, in a sense, of external nutrition) 

 and the cells. It thus bridges over, on one hand, the gap in the passage 



