ON THE ENDOTHELIUM OF THE BLOODVESSELS. 



BY 

 A. PIJPER M. D. (Bethal. S. A. R.J. 



Endothelium is the name used for the continuous layer of 

 more or less flat cells which line the inner wall of all blood- 

 vessels. Apart from small variations these cells are everywhere 

 of the same size and the same form, excepted in the spleen 

 and in the liver. In the spleen they present themselves in the 

 so called sinuses as longstretched and much thicker elements 

 with a strikingly big nucleus, whilst the liver possesses large 

 starshaped endothelial cells, known as KUPFER's cells. 



Of the functions of this endothelium little is known. In the 

 capillaries it probably plays an important part for the meta- 

 bolism, and recent publications i) exhibit a tendency to let 

 these endothelial cells account for the production and the 

 disappearance of oedema in nephritis. 



But on the whole the literature conveys the impression that 

 these cells have been neglected and especially no justice is 

 done to them in the study of immunity. There blood and blood- 

 serum attracted the attention to such an extent, that the view 

 was entirely lost sight of, that the knowledge of the properties 

 of the cells along which the blood flows might be of importance 

 for the knowledge of the properties of that blood. And yet 

 there are so many facts which demonstrate that the endothelium 

 is doing more than just convey the blood, it even does not 

 seem impossible that many properties of the blood and especially 

 those of importance for questions of immunity, are directly 

 derived from the endothelial cells. Experiments undertaken by 

 me on the advice of professor VAN CALCAR, and whose special 

 aim was to study the endothelium in the absence of any blood, 

 support this view completely. Beforehand I shall try to bring 

 older observations into accord with my views. 



