214 Transactions British Mycological Society. 



truly the organism is to be regarded as the physiological equili- 

 bration, the complex of reactions in the colloid substratum; 

 while the colloid substratum and the morphological structure 

 of the organism represent the "residue" from the metabolic 

 processes, the excess of intake over outgo. Nearly seventy 

 years ago HuXley(i8) wrote of the cells, the structural com- 

 ponents: "They are no more the producers of the vital pheno- 

 mena than the shells scattered along the sea beach are the 

 instruments by which the gravitative force of the moon acts 

 upon the ocean. Like these the cells mark only where the 

 vital tides have been and how they have acted." It will be 

 evident that any chemical substance which can be completely 

 utilised by the metabolic processes will not appear as a visible 

 part of the body of the organism. The body, the structure and 

 morphology of the organism, is a by-product of the metabolic 

 reactions. As such by-product can only escape from the cell 

 by decomposition, it constitutes therefore the more permanent 

 matter of the cell and appears as a visible substratum. It 

 may be regarded as residue left behind by the metabolic tides, 

 shewing how they have acted. 



Under identical conditions the structural substratum of 

 different organisms differs because the physiological constitu- 

 tion of the living matter of the organic individuals differs. 

 Thus the morphological distinctions between two species are 

 produced; but these divergent morphological facies are merely 

 the expressions of the differing physiological constitutions, and 

 have no permanent value or even existence apart from the 

 particular environmental conditions under whose influence 

 they are created. Under varying conditions the same physio- 

 logical constitution will give rise to different morphological 

 expressions and so one finds growth forms or "ecads." Under 

 recurrent identical conditions the same resultant will be 

 produced by the same physiological constitution giving con- 

 stancy of reaction in like environments. 



But just as, for example, a resultant of sixteen may be the 

 expression of various interacting factors such as four and four 

 or eight and two or sixteen and one, so, differing physiological 

 constitutions may under the influence of certain different 

 external stimuli produce the same resultant or "ecad." More- 

 over the force system representing the environment is infinitely 

 complex and it may often happen that two or more different 

 physiological constitutions may react with different smaller 

 force systems within the same environmental complex, so that 

 similar resultants ensue. Thus two distinct species may 

 under apparently identical conditions give rise to "ecads" 

 morphologically indistinguishable from each other. 



