in ELECTKICAL EXCITATION OF MUSCLE 303 



and a complete individual is formed again, although on a smaller 

 scale. With weaker currents the process generally stops short of 

 the collapse of vacuoles, only the gradual retraction of pseudopodia 

 on the anodic side is produced ; and there is no sign of any 

 kathodic break effect. The rapidity with which all the above- 

 described phenomena develop is greater with increased strength 

 of current. At closure of very strong currents the granular dis- 

 integration on the anodic side begins almost instantly, and then 

 progresses more and more gradually towards the centre as long as 

 the current is passing. 



According to Verworn the slow retraction of pseudopods on the 

 general body-surface that takes place during a prolonged passage 

 of current is to be regarded as a secondary process, arising from 

 the disintegration that has just taken place at the anode, and 

 stimulates the protoplasm, inasmuch as it always commences after 

 a considerable loss of substance has become apparent. 



From the above-described changes we may easily predict the 

 consequences of alternating currents. With moderately frequent 

 stimuli the pseudopodia at both poles begin to exhibit varicosities, 

 and also with stronger currents the granular break-down proceeds 

 part passu from both sides. It is worthy of note that with very 

 rapid reversal of current,, effects that are in progress become arrested, 

 to recommence with the adoption of a slower rhythm. 



Verworn pointed out that Polystomella crispa a marine 

 Foraminifer with numerous very fine pseudopodia, forming a com- 

 plex and retiform anastomosis, upon which the phenomena of 

 " granular currents " described by Max Schultze are well exhibited 

 reacts in precisely the same way to the constant current. " At 

 make of a current all the granules in the pseudopodia of the anodic 

 side begin to flow in a centripetal direction, and at the same time 

 are slowly retracted, and the longer the excitation continues so 

 much the fewer and shorter are the pseudopodia which protrude 

 from the cortex, until before long there is a total disappearance 

 of pseudopods on the anodic side." On the kathodic side no such 

 change is visible, the streaming of granules goes on as usual, and 

 the pseudopodia remain extended ; " they may even lengthen con- 

 siderably, or make their appearance at closure of the current at a 

 kathodic area previously free of pseudopods, the flow of granules 

 being now in a centrifugal direction." In this case, as before, 

 no change could be observed at or after closure of the circuit in 



