Plate I 



Fig. I "Mechanical hand" for moving a fine pointed instrument in stimulating Amcebae. When in 

 use it is clamped to the stage of a Zeiss binocular microscope (Greenough model) so that the whole appara- 

 tus except the point of the instrument lies to one side of the field of the microscope. When necessary two 

 can be clamped to the same microscope. A crude form of this apparatus, figured and described in an 

 earher paper (McClendon, '07), had the disadvantage of surrounding the field of the microscope on 

 three sides and sometimes colhding with the watchglass or slide on which the objects were placed. By 

 turning the milled head on the left an instrument held in the clamp is moved crosswise, by turning the 

 milled head in the center the instrument is moved back and forth, and by turning the one on the right 

 it is moved vertically, all three are held in the hand and turned by different fingers. 



Fig. 2 A simpler form of the same apparatus. The milled head moving the instrument vertically 

 is high above the other two. 



