Target theory criticism

Occasionally, one could have read about the failures of the Theory of Similarity or of its limits. However, this criticism has arisen when, due to some physical reasons, a complete similarity could not be achieved (see e.g. remarks of Damkohler [113] on p. 183) or the scale-up criterion could not have been worked out with certainty because the measuring conditions did not allow it (false model scale, wanted sensitivity of the target quantity, non-availability of the model material system, ignorance about relevant physical properties, such as in foams and sludges, etc.). 

Fig. 1. Schematic diagram outlining the neurotrophic theory of cell death. Neurons extend axons in the presence of a low circulating level of neurotrophic factors. At a critical point in their development, usually corresponding to the period of target tissue innervation, the neuron becomes acutely dependent on the neurotrophic factor for its survival. At this stage those that make appropriate connections in the periphery obtain sufficient factor for their survival. Those not making correct connections do not obtain sufficient factor and die.

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