139 



Ihc cytoplasm clear. Sonu'liines intor('slin<f morpholoffical 

 changes occurred. The pseudopods (hsapijeared aiid llie out- 

 lines of Ihe cells became very sharp. The cells looked per- 

 fectly like fibroblasts and the\- were liable to form anastom- 

 otic i)rocesses with other similarly differentiated cells (Fig. 29). 

 Often a long chain of cells could be observed and even a 

 chain would show the transition forms from the ameboid 

 cell in the distal pari of the chain lo Ihe perfect libro- 



Fig. 29. 

 Culture of a pure strain of mononuclear leucocytes undergoing differentiation. 



Eighth passage. 



From Carrel and Ebeling: Large mononuclear leucocytes. The Journ- 



of Exp. Med. 1922, XXXVl, 365. 



blasts in the central part of Ihc chain. Also in the stained 

 preparation the similarity to the fibroblast w^as very striking. 

 The outlines of the cells were very sharp, both ends drawn 

 out to a minute process, the nucleus very clear containing 

 two nucleoli. 



Experiments were undertaken by Carrel and E b e- 

 ling^*^) to see how the lymphoc3ies respond to different 

 amounts of embiyonic tissue juice in Ihe culture medium. 



