SINKING TENDENCY OF THE CORPUSCLES. 161 



crystal to its axes. Thus the colour of the reel molecules of the blood 

 is no incidental property, but, to its most delicate modifications, it 

 results from the idea of a vesicle which is filled with red fluid ; the 

 forms and dimensions of these vesicles are essentially changed by 

 various endosmotic influences, and thus give rise to the various 

 shades of colour. The form, the tendency to sink, and the specific 

 gravity, are also properties which always have a definite relation 

 and connexion. If, therefore, we consider the physical properties 

 of the blood-corpuscles from this point of view, we shall attain the 

 clearest conception of their nature, and obtain the firmest basis for 

 the support of our views regarding the mechanical metamorphosis 

 of matter occurring between these cells and the fluid surrounding 

 them. 



One of the properties which we observe, both in whipped 

 i. e. } defibrinated blood and also in blood on wiiich that operation 

 has not been performed, is the tendency of the coloured molecules 

 of the blood to sink, to a greater or less extent, in the intercellular 

 fluid. The difference in this sinking tendency of the corpuscles is 

 often extremely striking, both in physiological and pathological 

 conditions ; this phenomenon must consequently depend on some 

 other properties of the blood-cells. This difference was formerly 

 ascribed to the greater or lesser specific gravity of the blood- 

 corpuscles. It was generally believed, in accordance with the 

 views of Nasse, that this hypothesis was confirmed by the con- 

 stantly-observed fact that the colourless blood-cells did not parti- 

 cipate in this property with the red corpuscles, which differ so 

 essentially from every other cell-formation in the character of their 

 contents, which are of a tenacious fluid nature, and abound in iron. 

 To determine the value of this hypothesis by a more accurate 

 investigation, it would be necessary to institute more accurate and 

 comparative measurements of the density of the blood-corpuscles 

 and of the plasma ; but, unfortunately, such determinations were 

 not so easy of attainment to the earlier investigators as they 

 have since become through the ingenious deductions and investiga- 

 tions of C. Schmidt. It was, however, obvious, without such 

 accurate measurements, that at all events the specific gravity 

 could not be the sole cause of this sinking tendency ; for it was 

 long known that, by the addition of certain substances to the 

 blood, the sinking of the coloured cells was accelerated, while it 

 would naturally be expected that the intercellular fluid would have 

 been rendered denser by holding these substances in solution, 

 and that the assumed differences in the densities of the cells and 



VOL. II. M 



