'- 



134 THE EXCITATION OF AMCEBOID MOVEMENTS 



first one leucocyte and then in the others small bodies 

 like minute beads appear. These beads seem to come 

 from underneath the cell. The beads get larger, and 

 quickly develop into long snake-like processes of cyto- 

 plasm, which are extruded from the cell. In a few 

 moments every leucocyte in the specimen will appa- 

 rently be putting out these long "feelers" until the 

 cells may almost be said to look like tarantulas (fig. 28) . 

 There are usually two or three of these long pseudo- 

 podia extruded from each cell. At first the pseudo- 

 podia are composed of clear cytoplasm (fig. 29), but 

 later on a few granules from the cell are seen to move 

 into them. Leucocytes seem to endeavour to push 

 their pseudopodia into the crevices between the neigh- 

 bouring red cells if they can (fig. 30), although we 

 have no reason to give for this propensity. These 

 excited movements differ from ordinary amoeboid 

 movements in that they are far more exaggerated. 

 The picture of a field containing several excited 

 leucocytes is a striking one, for these movements are 

 very different from the ordinary sluggish amoeboid 

 movements seen when the cells are merely kept on 

 a warm stage. Moreover, it must be remembered 

 that we are using the room temperature and no warm 

 stage. 



The excited movements are due to the action of the 

 atropine. All the time, however, the stain is diffusing 

 into the cells as well as the alkaloid, and as time pro- 

 gresses the stain will reach the nuclei which now begin 

 to turn a faint blue colour. Now, it has already been 

 pointed out that the staining of the nucleus of a cell 



