696 Laura Florence 



not in the anterior, but toward the posterior, half of the stomach, in the 

 region of the bend cephalad; and in the last numbers of the series it was 

 found throughout the whole slender part of the stomach. 



In the cells containing the greatest number of granules, some were 

 seen resting on the basement membrane and a few appeared to be lying 

 among the muscle fibers outside the membrane, but sufficient evidence 

 to prove that they had passed through the membrane unchanged is wanting. 

 Whatever may have been the fate of these granules, they disappeared 

 from the cells, leaving in their places numerous vacuoles among which 

 the first traces of secretion were seen. The secretion accumulated in 

 the form of a compact mass, resembling a ball of thread, whose surface 

 layer takes a deep stain while the axis remains almost clear. This ball 

 pressed against the free ental border of the cell, pushing it into the lumen 

 and finally rupturing it. 



The above experiments show that aljsorption and secretion are carried 

 on by the same cells. In every section some cells, evidentlj'' in a resting 

 stage, are seen, but it is not clear whether the cells pass through this 

 stage after each secretion or at longer intervals. The formation of the 

 secretion appears to begin at the close of absorption, and, as the study 

 of the starved lice suggested, its excretion is stimulated bj^ hunger, so 

 that it is already present in the stomach when the blood is ingested. 

 No attempt has been made to investigate the exact nature of the granules 

 or the changes they may undergo, as this would necessitate a long series of 

 experiments with various reagents, such as were carried out first by 

 Fischer (1899) and later by Murlin (1902). 



If lice be fed as in the previous experiment, and blood smears be made 

 from the stomach contents at intervals of one hour and stained with 

 Wright's stain, the gradual action of the epithelial secretion on the blood 

 can be followed. Within one hour after feeding, the red cells become 

 vacuolated and fat globules appear, but the leucocytes and the platelets 

 are evidently not affected. The changes in the red cells continue until 

 only an amorphous mass remains, which, in sections stained with hema- 

 toxylin and eosin, can be recognized as a mass of brownish granules. 

 No blood platelets have been seen in any but one-hoin- smears. At two 

 hours the nuclei of the leucocytes are intact but their cytoplasm has been 

 attacked; there is a gradual change in its staining reaction, and after three 

 hours it takes the basic stain, appears light blue, and can be distinguished 



