428 A. E. HILTON OX THE STUDY OF THE MYCETOZOA. 



in the opposite direction ; but the cause of the phenomenon i^ 

 obscure. There is probably a tendency on the part of the Plas- 

 modium to liquefy interiorly, while becoming thinly membraneous 

 exteriorly; and where the plasm is in contact with surrounding 

 air or water, there are doubtless molecular disturbances, which 

 rapidlv, and perhaps rhythmically, alter the surface tension. In 

 this way alternate and opposite dilations and contractions of the 

 membrane may be produced, forcing the liquid contents first one 

 way, then the other. The fact, however, tha v , the whole mass 

 moves along shows that other influences are also at work, dis- 

 turbing the oscillating equilibrium of the surface tension, and so 

 making progress possible, or even inevitable. 



This short excursion into the dynamics of living matter brings 

 me to my main point, which is, that the supreme interest of the 

 Mycetozoa is biological. Of the " origin of life" — if the phrase is 

 permissible, which is doubtful — we have no certain knowledge, 

 perhaps never can have. But neither can we be " contented not 

 to know" ; and if ever a clue is obtained to the explanation of the 

 manifestations we call "life," it will probably be furnished by the 

 simplest of living things — not impossibly by those we are con- 

 sidering. Not that the Mycetozoa have left their record in the 

 rocks ; they are too frail for fossilisation. Perhaps they have 

 done even better, by preserving, almost unchanged, from remotest 

 times till now, vital forms which existed before organisms which 

 answer to our conceptions of plant and animal had been pro- 

 duced. If that be true, as some have thought, they are not so 

 much the evidence of a borderland between the two kingdoms as 

 survivors of a past epoch, less affected than the majority of other 

 organisms by the forces of evolution. Be that as it may, the 

 problems of biology seem, at least, to be in some measure simplified 

 in the Mycetozoa, by the fact that in their active stages they are 

 practically naked plasm, without many of the conditions which, 

 in more complex organisms, render those lu-oblems more obscure 

 and difficult to deal with. 



Enough has been said, I think, to show that the Mycetozoa,. 

 minute, mysterious, and beautiful as they are, offer an attractive 

 field of research, either as a recreation or a serious study ; and if 

 some of our members are led in that direction, the object of this 

 paper will be accomplished. 



Journ. Quekett Microscopical Club, Ser. 2, Vol. IX., No. 59, November 1900. 



