THE HISTOGENESIS OF DENSE LYMPHATIC TISSUE 185 



('Promyelozyten' of Pappenheim) , the granules of which later 

 transformed into true eosinophile granules. Still others found 

 the granules in these cells when first formed to be of a baso- 

 philic character, direct transformation and change later taking 

 place, the staining reaction of the granules changing from baso- 

 philic to eosinophilic character, at the same time as other changes 

 necessary to produce the adult eosinophile leucocytes are occur- 

 ring (Downey, '15; Ringoen, '15). 



The eosinophiles, occurring in the connective tissue of the 

 tunica propria and submucosa of the digestive tract, in the 

 region of the intestinal tonsils, occur in varying numbers, some- 

 times there being but a very few widely scattered, and again 

 being found as large, concentrated masses, or granulopoietic 

 foci. There is no definite time in development at which they 

 appear in greatest abundance, this being apparently controlled 

 by local conditions, varying according to the individual. They 

 are, however, never present in great numbers until after the 

 first week of postfetal life. Also, as stated before, they are 

 almost invariably more abundant in the wall of the caecum and 

 the appendix than in the iliac tonsil. 



Their distribution in the connective tissue has already been 

 spoken of. They are usually in greatest abundance in the tunica 

 propria, especially around the bases of the typical, ordinary 

 villi (figs. 10, 11, 16) (except isolated cases where large granulo- 

 poietic foci were found in the subnodular connective tissue). 



A careful study of the eosinophile granulocytes as found in 

 these places makes evident the fact that they are morphologi- 

 cally of two types, 1) the blood eosinophile and, 2) the connec- 

 tive-tissue eosinophile. 



The first type, as the name given indicates, closely resembles 

 the eosinophile leucocytes found in the blood stream. The cell 

 is of a rounded form and contains a very polymorphous richly 

 chromatic nucleus. The contained granules are rounded or 

 slightly elongated (as those of the blood stream), and are packed 

 quite closely together' within the cytoplasm of the cell. With 

 blood stains (as Hastings-Nochts) these granules stain a bright 

 red color. 



