Physical Asyects of Protoplasmic Streaming 235 



An important reason why the components postulated for one 

 portion of the curve can not represent other portions seems to be the 

 instability of the components. This means that the components them- 

 selves are not kept constant during an experiment; in other words, a 

 dynamoplasmogram contains variable components. Even when the 

 extrinsic factors are kept constant, the intrinsic factors of the proto- 

 plasm change spontaneously. For instance, as the protoplasm spreads 

 during an experiment, the surface-volume ratio of the plasmodium 

 may change; this will affect intraplasmic diffusion involved in many 

 physiological processes, especially in respiration. Change in intra- 

 plasmic diffusion is but one of the factors which possibly alter the 

 components of the rhythmic motive force and so restrict the analysis 

 to that portion of the curve which represents the period of an experi- 

 ment. 



Spontaneous change in polarity, no matter what the real physico- 

 chemical meaning of polarity may be, also disturbs the dynamoplas- 

 mogram pattern. Polarity factors are also in part responsible for the 

 fact that components postulated for one portion of a dynamoplasmo- 

 gram can not represent other portions of the same dynamoplasmo- 

 gram beyond the limit of the time scheme. The meaning of polarity, 

 physically or chemically considered, is not clear, but it may be 

 considered as an entity apart from rhythm. Watanabe, Kodati, and 

 Kinoshita (1937) found that the anterior portion, in the direction 

 toward which the plasmodium advances as a whole, has always a 

 higher electric potential than the posterior part, although potential 

 difference between the anterior and posterior parts show a close 

 correlation with the rhythmic reversal of flow. It is probable that 

 the potential difference is, in some way, connected with the polar 

 nature of the motive force, if it is not the direct cause of the polarity 

 of the motive force. 



To sum up, it is obvious that the rhythm of the motive force is 

 modified, to a greater or lesser extent, by internal factors under 

 constant external conditions. 



The waves shown in Figure 9 change their amplitude and form, 

 but the periods of increased and decreased amplitude continue for 

 an irregular duration of time. There is no regularity, either in 

 regard to the wave form or to the change in amplitude. Nevertheless, 

 the basic rhythm must operate according to a regular rhythmic pat- 

 tern. Such a curve is regarded as containing many subordinate 

 components, the frequencies of which are not in simple ratios to one 



