SECT. 2.] INTRODUCTION. 3 



However, should it ever be possible to discover even the molecules 

 which form the cell membrane, the muscular fibrillar the axial 

 fibres of the nerve, etc., and to fathom the laws of their opposition 

 and alteration during- the origin, growth, and functional activity 

 of the elementary parts, as they are now called, a new era in His- 

 tology would commence, and the discoverer of the law of cell- 

 origin, or of a molecular theory, would be as much, or still more, 

 extolled than the founder of the doctrine of the cellular com- 

 position of all animal tissues. 



§ 2. Were we to characterise the present position of Histology 

 and its object somewhat more minutely, we must not forget that 

 that object is, properly speaking, only to study one of the three 

 aspeets which present themselves in the elementary parts of the 

 body, as in the organs, namely the form. Only to take cognizance 

 of the microcospic forms, and to investigate the laios of their structure 

 and formation, is that upon which microscopical anatomy proceeds ; 

 but not to be a doctrine of the elementary parts in general. Ac- 

 cordingly, the chemical composition and functions come, properly 

 speaking, into question only in so far as is requisite in discovering 

 their relation to the origin of the forms and their diversity. 

 Everything else met with in histology, concerning the functions of 

 the fully developed elements of their chemical conditions, is either 

 taken in from practical considerations, or is only taken as closely 

 allied, so long as physiology does not assign a proper place to the 

 functions of the elementary parts. 



If Ave wish to raise Histology to the rank of a science, our first 

 task consists in obtaining for it a broad and sure objective basis. 

 To this end, the intimate morphological conditions of the animal 

 organisms are to be explored in every phase, and, indeed, not 

 onlv in adult animals, but also in all earlier periods, from the 



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first development onwards. When the morphological elements 

 are fully known, we have then to investigate the laws according 

 to which they have arisen, grown, and ultimately arrived at 

 their permanent form; during which their chemical conditions 

 and functions cannot but be taken notice of. In order to find out 

 these laws, the accidental and non-essential will, as in empirical 

 sciences in general, by continued observation be separated more 

 and more from the always present and essential, until at last a 

 series of general empirical propositions results, for which, then, 

 mathematical expressions or formulas will be deducible, and thus 

 the laws found out. 



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