3 28 



A. A. SCHAEFFER. 



EXPLANATION OF PLATES. 



The figures are camera lucida drawings taken from the laboratory notes without 

 alterations. The camera lucida was attached to the right hand tube of a long 

 arm Zeiss binocular microscope. Eyepiece 4 and objective a a were used, giving a 

 magnification of 65 diameters. A scale by means of which the size of the amebas 

 and of test objects can be estimated is shown on Plate 7. 



The figures are numbered serially from i on for reference. An x following a 

 number, as gx, indicates the end of the experiment illustrated by Figs. 6 to px 

 inclusive. A new experiment starts with Fig. 10 and ends with Fig. I2x, and so on. 

 If a number is followed by xx, it means that the next experiment was performed 

 upon a different ameba. Thus Figs. 6 to 2?xx represent the results of several 

 experiments upon the same ameba. With Fig. 28 a new ameba was employed, 

 and so on. The order in which the figures were drawn is represented by the serial 

 numbers for all the figures in any one experiment, and in nearly every case for all 

 the experiments performed upon any one ameba. 



The time of the beginning and the end of each experiment is given in hours and 

 minutes. In many cases the time of drawing of each figure is also given, and where 

 it is not given it may easily be computed. 



The arrows show the direction of active protoplasmic streaming. The arrows 

 in the last figure of each experiment denote the direction the ameba took in moving 

 away from the test object. 



The test objects are labelled in abbreviated form. See table of abbreviations 

 below. For quick and correct reference the test objects are connected with the 

 proper ameba by leader lines. These lines have no other significance. 



All the work was done facing a north window. All the figures were drawn in 

 the same position in the laboratory and on the plates. The top of each plate there- 

 fore points toward the north. This is worth noting from the point of view of the 

 possible influence of light on the behavior of ameba. 



It will be noted that there are slight differences in the size and shape of the 

 same test object as drawn in the figures of any single experiment, even if the object 

 was not rolled around by the ameba. The explanation for this difference lies in 

 the speed with which the drawings had to be made in order to catch important 

 items of behavior. As a rule the parts of the ameba lying nearest the test object 

 received the most careful attention and were drawn first; the posterior parts of 

 the ameba and the test object were drawn last. 



For detailed explanation of figures see text. 



TABLE OF ABBREVIATIONS. 



AR, arrowroot starch grains. GE, gelatin. 



ARP, arrowroot starch paste. GL, glass. 



C, carmine solution. GR, graphite. 



CA, carbon. H, hematin. 



CH, cholesterin. IN, indigotin. 



E, egg albumin solution. P, peptone. 



FC, food cup. PB, lead oxide. 



FL, flagellates. 5, silicic acid. 



G, globulin. T, tyrosin. 



