206 THE LAW OF JOHANNSEN. 



It is entirely feasible to imagine combinations of autokat- 

 alytical substances which have no structure, and no "body", 

 but which nevertheless, when occurring together manifest 

 their presence in a way which is different from the action of 

 each alone. (Filterable virus). Causes which destroy the physic- 

 al relationship between the constituents of protoplasm may 

 cause death, that is, the relationship as such may be self-con- 

 tinuing, and destruction may be irreversible. On the other 

 hand physico-chemical structural relationships are not neces- 

 sarily dependent upon combinations of several constituents. 

 The formation of a crystal in a super-saturated solution is an 

 autokatalytical process in which the structure can be irrepar- 

 ably destroyed. 



The conception of living matter as a combination of auto- 

 katalytical constituents makes the essential thing in living 

 independent of its more usual manifestations. A small, dry 

 crystal in a closed vial in a cold environment, is as full of latent 

 life in the narrowest sense as a dry seed under the same cir- 

 cumstances. 



A combination of even two things can have a set of qualities 

 of its own, quite different from those of its constituents, but it 

 is evident that the continued reproduction of both constit- 

 uents is essential for the continued existence of the combination. 



Variations in the proportion in which the algae and the fung- 

 us mycelium occur in the combination, which we call a lichen 

 will produce variations in the properties of the lichen. 



A fragment of a lichen may for a time reproduce its quali- 

 ties, in as far as they are dependent upon a certain proportion 

 of the constituents. But it is clear that a small mass of the 

 lichen, will have the same potential possibilities of differen- 

 tiation, only so long as it includes both constituents. 



In the same way, the possibilities of a cell, or of a series of 

 cells, are plainly given in the different relative quantitative 

 proportions in which its constituents can occur. 



Within the limits of a continuation of life, one or several 

 cell-constituents can become predominant in the combination, 



