220 The Structure of ProtojplasTn 



decreases in this case. The distance between any two adjacent 

 maxima and minima of the waves is nearly constant for about 117 

 seconds. 



Figure 12 shows another pattern of the rhythm. In this figure, the 

 crest is acute, while the trough is flat. The magnitude and the period 

 (ca. 132 seconds) are greater than those of Figure 11. Though the 

 amplitude diminishes gradually, as in Figure 11, the wave form re- 

 mains similar in each rhythm. The dash-dot line and the dotted 

 waves will be taken up later. 



VII. GENERAL CHARACTERISTICS OF DYNAMOPLASMOGRAMS 



The graphs presented in this paper are some of the representative 

 cases of more than 40 wave trains so far obtained in my experiments 

 with different specimens. By inspecting these graphs one can sum- 

 marize their general features as follows: 



1. The pattern of the curve undergoes variations from rhythm to 

 rhythm in the same specimen under the same external conditions. 



2. A marked change in amplitude sometimes recurs at regular 

 intervals (Figs. 7 and 8) , but this regularity is not always maintained, 

 even though the waves continue to change amplitude (Fig. 9) . 



3. A similar wave form often reappears throughout several suc- 

 cessive rhythms (Fig. 10) . Changes in the wave form as well as in 

 amplitude are transitional (Figs. 11 and 12) , 



These general characteristics of the curve are, however, open 

 to possible question. One may wonder whether or not the peculiar 

 pattern of the wave has anything to do with a "grafted" plasinodium, 

 in which three separate portions (two protoplasmic blobs and a 

 connecting strand of protoplasm) were united in preparation. This 

 is answered by the fact that a plasmodium, the form of which, with- 

 out grafting, has been so changed that there are two protoplasmic 

 bodies connected by a single strand, also shows characteristics in 

 its dynamoplasmogram which are identical to those of the grafted 

 one. 



In viewing the foregoing graphs, it is to be noted that the curves 

 show no sign of a special deflexion when they cross the base lines; 

 in other words, the points which correspond to the moviejit of rever- 

 sal are not characterized at all by the shape of the curve. Previous 

 investigators have almost implicitly adopted the moment of reversal 

 of flow as the only criterion for distinguishing one rhythm from 

 another; for other than this, there has been no gauge with which to 



