Munson, Organization and Polarity of Protoplasm. 371 



mere platitude to say, of these, that Organization determines the 

 functions of the organism. To what extent can functions exist 

 in the absence of Organization ; does the one precede the other ; or 

 have function and Organization developed simultaneously, out of 

 matter devoid of both strukture and function? 



In my studies on the cell, I have kept these problems in 

 mind; and it is my purpose here to present some observations bear- 

 ing on these questions. 



I. 

 Externa! Evidences of Polarity. 



Fore and aft Polarity. — In A moeba verrucosa, 

 fig. 1, pl. I, there is a definite differentiation of an anterior and 

 a posterior end. A line connecting these two ends constitutes a 

 longitudinal axis, which divides this Amoeba into two approxi- 

 mately similar halves, — a right and a left side, — which con- 

 stitutes bilateral symmetry. 



The dorsal side is characterized by longitudinal folds, grooves, 

 and ridges, usually four or five in number. They seem to be the 

 outer expression of internal movements of the granules in the 

 protoplasm. The ectosarc is of considerable thickness, and is dif- 

 ferentiated from the granulär endosarc. I have succeeded in remo- 

 ving the endosarc leaving the ectosarc as an empty shell, the lon- 

 gitudinal lines still showing. 



The granules of the endosarc move constantly towards the 

 anterior end; and the Amoeba moves, as a whole, in that direction. 

 This movement is not always in the direction of light. It is often 

 opposite to the force of gravity; and it cannot always be accounted 

 for by assuming that the Amoeba is attracted by oxygen. 



In Amoeba villosa, fig. 2, pl. Ia, a similar fore and aft po- 

 larity is evident. But the differentiation of the two ends is here 

 still more marked. The external, longitudinal lines are not so 

 evident as in Amoeba verrucosa; but the body, as a whole, is more 

 elongated ; and the posterior end is distinguished by a villous Pro- 

 longation. The surface of this part of the Amoeba appears rough- 

 ened, as if covered with short, thick ciliary processes or papillary 

 villi. This form, too, has a longitudinal axis and bilateral sym- 

 metry. The granules of the endosarc move uniformly towards 

 the anterior end, which shows a considerable development of 

 ectosarc. 



Dorso-ventral Differentiation. In Arcella 

 discoides, fig. 3, pl. Ia, there is evidence of a radial symmetry and 

 a dorso-ventral differentiation. This Amoeba lives in a shell, 

 which is somewhat hemispherical in shape, being flat or concave 

 underneath and convex above. In general outline, the shell is 



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