SOME OF THE WAYS OF THE SLIME-MOULD 



Thomas H. Macbride 



A recent volume by Professor D'Arcy W. Thompson, bearing 

 the terse title " Growth and Form," seems to me for the mycologist 

 very suggestive, and to that extent, at least, one of the most useful 

 among the books of later years. A paragraph from its pages 

 might form the text for the discussions of the present paper. 

 After developing at length and very clearly the various problems 

 of tension, particularly as determined by molecular attractions, in 

 liquids mass-tensions, surface-tension and their interactions, the 

 author applies to TEthalium, a common slime-mould, the same 

 principles applicable to so much water, assuming the myxomycete 

 to have the same specific gravity, and both liquids placed for ex- 

 periment under similar conditions. The paragraph, too long for 

 quoting here, is noteworthy for two reasons : in the first place it 

 presents, as is believed, the first citation of a slime-mould anywhere 

 or at any time in a court of physical research; and in the second 

 place, it is the first attempt, so far as I have noted, to refer the 

 phenomena especially characteristic of the organisms in question 

 to forces purely physical in nature — i.e., to such as are familiar 

 to the laboratories of purely physical science. 



In these days of refined and beautiful physical research chemical 

 and physical reactions are so interrelated that only the most accom- 

 plished expert in either or both fields may venture their mention,., 

 not to say discussion. The present writer makes no pretension ; 

 but there are in the life history of the slime-moulds certain pecu- 

 liar facts, patent to ordinary observation, always worthy of study 

 and, as it would seem, deserving, for thorough apprehension, not 

 to say comprehension, all the help that physical science may afford. 

 Professor Thompson's argument is very helpful, and yet — as illus- 

 trating the way of the slime-mould — permit me to summon the 

 chief offender. 



In 1876 Sachs in the one-time classic Physiology, discussing 



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