368 



E.. V. COWDEY 



quite different The compensatory hypertrophy of true lymphatic tissue 

 following removal of the thymus, as recorded by Basch (a,), is an interest- 

 ing argument in favor of the lymphatic nature of the small cells, but 

 requires confirmation. 



Cytology of "Small Cells." The small cells are placed in a reticulum 

 formed by the separation and attenuation of the original epithelium and 



Fig ; 6. HassaH's corpuscle in an 8-day-old rabbit prepared to show the mitochon- 

 dria. Note the difference in the properties of the mitochondria in the epithelial cells 

 (e), and lymphocytes (1); the progressive disappearance of mitochondria as one 

 approaches the center of the corpuscle; and the mode of deposition of the hyaline 

 material (magnification 1500). 



the penetration of connective tissue. They contain mitochondria which 

 to all appearances are identical with those occurring in lymphocytes. 

 They present no indications of secretory polarity and 110 traces of secre- 

 tion antecedents have ever been found. The nuclei of these small cells 

 are characteristically lymphocytic, possessing a strong affinity for basic 

 dyes. The chromatin is also disposed in the same way in both (Fig. 5). 

 The Reticulum. The cells of the reticulum may easily be recognized 

 by their large, pale staining nuclei and by their irregular outlines. More- 

 over, they contain distinctly smaller mitochondria (e) than the small 



