DEFINITIONS OF LIFE. 25 



causd) to imagine shell coextensive with the organized 

 creation, this would produce no abatement in the falsity 

 of the reasoning. Nor does the flaw stop here ; for a 

 physiological, that is a real, definition, as distinguished 

 from the verbal definitions of lexicography, must consist 

 neither in any single property or function of the thing 

 to be defined, nor yet in all collectively, which latter, 

 indeed, would be a history, not a definition. It must 

 consist, therefore, in the law of the thing, or in such an 

 idea of it, as, being admitted, all the properties and func- 

 tions are admitted by implication. It must likewise be 

 so far causal, that a full insight having been obtained 

 of the law, we derive from it a progressive insight into 

 the necessity and generation of the phenomena of which 

 it is the law. Suppose a disease in question, which ap- 

 peared always accompanied with certain symptoms in 

 certain stages, and with some one or more symptoms in 

 all stages say deranged digestion, capricious alternation 

 of vivacity and languor, headache, dilated pupil, diminished 

 sensibility to light, &c. Neither the man who selected 

 the one constant symptom, nor he who enumerated all 

 the symptoms, would give the scientific definition talem 

 scilicet, quali scientia fit vel datur, but the man who at 

 once named and defined the disease hydrocephalus, pro- 

 ducing pressure on the brain. For it is the essence 

 of a scientific definition to be causative, not by in- 

 troduction of imaginary somewhats, natural or super- 

 natural, under the name of causes, but by announcing 

 the law of action in the particular case, in subordination 

 to the common law of which all the phenomena are modi- 

 fications or results. 



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