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ON THE CAUSE OF REVERSING CURRENTS IN THE 

 PLASMODIA OF MYCETOZOA. 



By A. E. Hilton. 



{Read March 20th, 1908.) 



The active plasmodiurn of a Mycetozoon is a naked aggregation 

 of plasm, which has two characteristic movements : a streaming 

 movement of the interior and more liquid plasm, as distinguished 

 from the firmer exterior plasm ; and an amoeboid movement, by 

 which the whole mass changes its form, and travels about. The 

 two processes are so closely related that a description of the one 

 necessarily involves allusions to the other ; but they are sufficiently 

 distinct for separate consideration, and the scope of this paper is 

 limited to the cause of the streaming movements of the interior 

 plasm. 



Text-books on the Mycetozoa describe this phenomenon, but 

 offer little explanation. In 1884 Professor de Bary, by whom 

 the name Mycetozoa, " fungus-like animals," was first applied to 

 the organisms previously called Myxomycetes, " slime-fungi," 

 stated that " the internal causes of the change of shape, of the 

 protrusion and withdrawal of processes, and the interior streaming 

 of granules, were to a great extent unknown." Mr. Massee, in 

 his monograph published in 1892, did not discuss the question. 

 Mr. Lister's monograph, issued in 1894, mentioned that the 

 cause of the rhythmic streaming of plasmodia had not then 

 been ascertained ; and as the Guide to the British Museum 

 Collection, revised by him in 1905, describes the streaming, 

 without offering any conjecture as to its origin, presumably no 

 adequate explanation was forthcoming even at that recent date. 

 In Wonders of Life, however, published in 1904, Haeckel stated 

 that attempts had been made to explain the phenomenon on 

 purely physical principles ; and further that experiments by 

 Ernest Stahl on Aethalium septicum had shown that the counter- 

 movements in the Mycetozoa are provoked by a peculiar form 



Journ. Q. M. C, Series II.— No. 63. 20 



