Physiology. — ''On the Behaviour of Megakaryocytes in the Spleen 

 of the young Kitten". By J. J. L. De Neve. (Communicated 

 by Prof. J. Boeke). 



(Gommunicaled in the meeting of December 23, J 91 7.) 



/. Introduction. 



' It is a well known fact, though hardly any mention is made of 

 it in the literature, that in the normal mammalian spleen the giant- 

 cells (which have been named mega- or megalokaryocytes by W. 

 H. Howell, 1890) of embryonic life persist after birth. Nay, several 

 French investigators, notably Jolly and Rosello (1909), and 

 especially de Kervely (1912) have discovered that giant-cells are 

 demonstrable in the normal full-groAvn spleen of most mammals. 



They are, however, far more numerous in the embryonic than 

 in the adult spleen. To find out the way in which this dimi- 

 nution in number takes place, has been the object of ray research. 

 I set myself the question : in what way and when do megakaryocytes 

 disappear from the spleen of the cat. I presume to have found the 

 answer to this question. 



77. The Literature. 



Giant-cells in the liver and in the umbilical vesicle have been 

 oftener described than those in the embryonic spleen, because most 

 investigators, writing about this subject, have studied the youngest 

 stages of hematogenesis. Now the spleen is of comparatively late growth, 

 when the bloodrelations are already so complicate as to present 

 insuperable difficulties for a study of the formation of the blood. Besides, 

 another difficulty is met with in the complicate structure- and tissue- 

 relations that soon arivSe in the spleen itself. This, however, does not 

 interfere with our study, since it regards only one special type of cells. 



Assuming the giant-cells to perform some function, the disap- 

 pearance of the cell must in one way or other be connected with 

 this function. We, therefore, deemed it interesting to consider the 

 views adopted by others. 



Van der Stricht is among the first to discuss this point (J 888 and 



