32O A. A. SCHAEFFER. 



was formed. A small mass of this gel was placed in the path 

 of an ameba 303. The ameba moved forward with a little 

 uncertainty 304, 305. Presently, however, the ameba began 

 to move in a concerted manner and when the main pseudopod 

 was about one fourth past the starch paste, a pseudopod was 

 sent out toward it, but the pseudopod was retracted before it 

 came quite into contact with the paste. The forward movement 

 of the ameba did not seem to be disturbed by the projection of 

 the small side pod. The behavior of the ameba toward arrow- 

 root starch paste is very similar to that toward gelatin. 



REACTIONS TO SUBSTANCES IN SOLUTION. 



Solutions of certain substances were allowed to run into very 

 fine capillary glass tubes, after which one end of them was 

 sealed hermetically with heat. The tubes were made a centi- 

 meter or more in length so that the substance at the open end 

 of the tube would not be affected by the heat employed in sealing 

 the other end. The external diameter of the tubes was about 

 twenty-five microns, and the bore about fifteen microns, but 

 there was some variation in the dimensions of the different tubes. 



The solutions were placed in small tubes, for it is necessary 

 to localize as definitely as possible the diffusion currents from 

 the open end of the tubes in order to be certain of the meaning 

 of the behavior which might be observed. But even with the 

 employment of capillary tubes the results are more or less 

 uncertain, unless the reactions are decided or repeated often; 

 for, the solutions being in most cases colorless, the extent of their 

 presence outside of the tubes can only be inferred. 



Peptone. From meat. Commercial, from Eimer and Amend. 

 As is well known, this substance is very soluble in water and has 

 a very strong agreeable smell and "taste." The taste is salty. 

 The action of peptone resembles that of meat extracts upon the 

 human senses. 



A capillary tube filled with a dilute solution of peptone was 

 placed in the path of a raptorial ameba 333. The ameba moved 

 toward the open end of the tube and formed a large food cup 

 before coming into contact with it, but the food cup finally 

 closed in over the open end of the tube 334. The ameba 



