114 ANDREWS. 



for long days upon a mountain peak, but which when climbed 

 to and met in close encounter, are found to be hurtling masses 

 of vapour, rushing powerfully against the crag on one side and 

 melting away like an elusive memory as they strike a wall of 

 warm air just beyond, while every foot, every inch, of those 

 square miles of vapour is stir and changeful difference. 



[104] The marvels of filose phenomena have been dwelt on 

 at length. It is not undue emphasis has been given them 

 for they are by far the most widespread and most characteristic 

 phenomena of the substance, if we except contractility. 



In ordinary amoeboid movement there are two sets of phe- 

 nomena to be reckoned with; a purely passive flow governed 

 by impetus received from local substance contractions; and a 

 more mingled flow in which the same cause lasts longer and 

 passes as a wave of contraction along certain lines of the sub- 

 stance causing more or less steady and continuous displacement 

 before it of the substance in its path — like that of interalveolar 

 substance along the fibrils, or as in filose phenomena.^ 



In amoeboid displays the structure of Biitschli or a coarser 

 is largely implicated, the finer foam of the continuous sub- 

 stance being of course involved. In true filose activities the 

 displacement is limited to the finer froth. This expresses I 

 think, the whole ground of difference between them. I do 

 not deny to protoplasm motion of the sort which Biitschli 



1 Having spent hundreds of hours in watching the flow of amoebae as well as 

 of many other and diverse Protoplasta both lobose and filose, besides Myxomycetes; 

 I venture thus to express myself counter to certain widely accepted opinions. The 

 phenomena have been looked at too much from a standpoint which accepts the 

 most obvious phenomena as of prime importance, using these for the starting point 

 of observation; and which is further baffled by that most treacherous of all rela- 

 tions, a time, or sequence, relation, 2Lrgmng post hoc ergo propter hoc. The subtlety, 

 complexity, and fleetingness, of protoplastic phenomena at their simplest, together 

 with the fact that at any given moment many causes and many effects are crossing 

 each other as impulses and impulsions of fluid and readily displaced substance ; 

 have seemed to me to make the study of amoeboid phenomena quite other than 

 one could imagine from any printed description to be met with. One might easily 

 give a lifetime to unravelling these phenomena and without much result if one 

 followed the established precedent in this line, that is, looking for and seizing upon 

 change of external contour, and grosser internal and external displacements and 

 correlating these which, as a matter of fact, apart from mere mechanical displace- 

 ment caused at times by impetus of one or another, have usually little or no vital 

 relation to each other. 



