42 THE GENERAL CHARACTERS OF CELLS, BY S. STRICKER. 



means by which certain varieties of structure can be recognized, 

 and we have also learnt that even when cells are apparently 

 in contact an intermediate material is present, by which they 

 are cemented to one another. Recklinghausen has by the use of 

 this method rendered certain markings apparent in the finest 

 lymphatics ; and Eberth, Aeby, and Auerbach* have by similar 

 means exhibited peculiar patterns in the blood capillaries, whilst 

 similar lines may generally be brought into view wherever 

 cells lie in apposition. 



A difference of opinion exists in regard to the significance of 

 the lines brought out by silver in the blood capillaries. Those 

 who oppose the ordinary view base their opinion upon the history 

 of development, from which we learn that the blood capil- 

 laries commence as solid fibres, and then become hollow ; but 

 we also know, through the investigations of Reitz,f that the 

 villi of the placenta commence as solid fibres, which subse- 

 quently become hollow, and that after the occurrence of an 

 abundant proliferation of nuclei the sheath of protoplasm 

 of these now hollow processes undergoes differentiation into 

 cylindrical cells. We thus see that a considerable mass of 

 protoplasm can become differentiated into cells. 



The formation of the blood capillaries must be described in 

 a similar manner ; they commence after the fashion of a gun 

 barrel with smooth bore, but subsequently appear like the shaft 

 of a chimney ; cell boundary lines, or, more correctly speaking, 

 lines of connective substance, being developed in their wall. 



The consideration of this process teaches us that the cement 

 is to be regarded as proceeding from the metamorphosis of the 

 cell substance, and is therefore properly included in the series 

 of intercellular substances. Cells may either present flat 

 surfaces in apposition to each other, or they may present 

 small processes, dentations, or striae, by means of which they 

 cling to one another like the bristles of two brushes. J They 

 may also become attached to one another partly by means 

 of flat surfaces and partly through the intercalation of the 



* Centralblatt, 12, 13, 14, 1SC6. 



t Wiener Sitzungsbenchie, 1838. 



J Max Schultze, Centralblatt, 1SG1, Xo. 12. 



