EQUIVALENCE OF DIFFERENT HEMATOPOIETIC 



ANLAGES. (BY METHOD OF STIMULATION OF 



THEIR STEM CELLS) 



I. SPLEEN 



VERA DANCHAKOFF 



The Wistar Institute of Anatomy and Biology 



TWO TEXT FIGURES AND NINE PLATES 



1. Introduction. Statement of the problems of hematology. Different 



methods of attacking the problems. Myeloid metaplasis. Statement 



of the problem of the present paper 255 



2. Methods of investigation and terminology 267 



3. Histogenesis in the spleen in relation to structural environment 274 



A. Histogenesis in the normal chick spleen 274 



B. Histogenesis in the chick spleen after stimulation 285 



a. Changes after stimulation in early stages 287 



h. Changes obtained by stimulation in the stage with definite 



spleen vascularization 294 



C. Conclusions. Data concerning: a) the histogenesis of spleen cells, 



6) the conception of cell differentiation, histogenesis, c) the 

 general meaning of myeloid metaplasis 296 



1. INTRODUCTION 



Statement of the prohlerns of hematology. Different methods of 

 attacking the problems. Myeloid metaplasis 



The special hematological literature has been rapidly and 

 constantly growing during the last decade, and there is enough 

 ground to anticipate a further specialization in this partial 

 domain of biology. Surveying the voluminous hematological 

 literature, one is astonished by the discrepancy between the 

 simplicity of the fundamental problems of hematology and the 

 entanglement which they have undergone during the last 



255 



THE AMERICAN JOURNAL OP ANATOMY, VOL. 20, NO. 3 

 NOVEMBER, 1916 



