270 A. E. HILTON ON THE PLASMODIA OF MYCETOZOA 



Professor de Bary remarks that " if single cells of a sclerotium 

 are watched, contractile vacuoles are seen to form in them, a few 

 hours after they are moistened, and protrusion of motile branches 

 and pseudopodia and the creeping forward movement, all begin as 

 in plasmodia." In this passage he so closely associates the con- 

 tractions of the vacuoles with the other visible activities of the 

 Plasmodium, that it is remarkable he nowhere suggests a relation 

 of cause and effect ; but he probably referred all these phenomena 

 alike to the plrysiological constitution of the plasmodium, without 

 stopping to consider them as possible links in a chain. 



At this point, for the present, my inquiry ends, because the 

 subject of this paper is restricted to the cause of the streaming 

 movements ; and therefore the ultimate physiological explanation 

 is only implicated so far as it is necessary to support the physical 

 explanation. But if it is a fact, as I believe, that pressure and 

 suction, originating in rhythmic dilations and contractions of 

 a slow respiration, are the main cause of the alternating currents, 

 a plasmodium is an organism in which the biological processes 

 are so abbreviated that in the most direct manner conceivable 

 the functional energy by which it breathes is converted into the 

 physical force by which it moves. In no simpler way can we 

 imagine an organism living and moving, and maintaining its 

 being. 



Journ. QvArtt Microscopical Club, Ser. 2, Vol. X., No. 63, November 1908. 



