AMEBOCYTES WITH SPHERULES. 



149 



stain or with Ehrlich's triacid blood stain; others were fixed 

 and stained by Wright's method ; and those of a third group were 

 fixed in the fumes of 2 per cent, osmic acid. By far the best and 

 most uniform results were obtained with the HeJly-triadiL 

 preparations. In addition to the smears, parts of the intestine 

 were fixed in Helly's fluid, embedded in paraffin, sectioned at 7 

 microns, and stained with Ehrlich's triacid stain or with eosin- 

 azure II. The eosin azure gave the most satisfactory results. 



OBSERVATIONS. 



Fresh Perivisceral Fluid. The cellular elements present in the 

 fresh perivisceral fluid of Arbacia have already been described 

 in detail (Kindred, '21), hence a brief description of these cells 

 will suffice here. The leucocytes are small, have a granular 

 endoplasm containing clear vacuoles (acid to neutral red), and 

 bear varying numbers of flap-like pseudopodia (Fig. i). These 

 cells have been observed to be phagocytic, thrombogenic and 

 scleroblastic. 



FIG. i. Cells from fresh perivisceral fluid, a, leucocyte; b, amebocyte with 

 colorless spherules; c, amebocyte with red spherules. X 1200. 



Amebocytes containing either colorless, red, or yellow spherules 

 are present in all drops of perivisceral fluid (Fig. i). The 

 amebocytes with red spherules are the most numerous, those 

 with colorless spherules next, and those with yellow spherules 

 least numerous. None of these cells have been observed to 

 be phagocytic, thrombogenic, or scleroblastic. They move by 

 means of blunt pseudopodia. These cells possess distinct cell 

 membranes. The colorless spherules are larger than either the 

 red or yellow spherules which are approximately of the same size. 

 The nucleus of an amebocyte appears as a light area near the 

 center of the cell. 



