332 SPECIAL HISTOLOGY. 



to Lehmann, in which they are characterised by their very 

 various size {via 1 . § 223) ; I have noticed this, in many cases, 

 though by no means invariably, but am unable to regard it 

 as an exclusive character of the blood in the hepatic veins, be- 

 cause I have also found the same multitude of colourless cells, 

 in perfectly healthy animals, in the portal blood, as Lehmann 

 has done in one case, as well as in the blood of the pulmonary 

 veins. Otherwise, however, the colourless cells are more abun- 

 dant in the venous, than in the arterial blood (Remak). In 

 the vena cava superior, and iliac vein of the Dog, Zimmermann 

 noticed uninuclear cells, and, in the v. cava inferior, multi- 

 nuclear ones. 



[Many experiments have already been made as to the in- 

 fluence of various reagents on the blood-globules, although 

 the results obtained have in some measure been of very trifling 

 importance; and I, therefore, here adduce, chiefly from my 

 own researches on the subject of the human blood-corpuscles, 

 only what may serve to illustrate their anatomical and physio- 

 logical relations. Water at first renders the blood-globules 

 spherical, and, owing to the diminution of the broad diameter, 

 consequent upon the increased thickness, smaller (from 0*002 — 

 , 0024 /// ), which may be best seen in corpuscles arranged in 

 columns. The size then usually remains without further 

 change, and the colouring matter and remainder of the contents 

 slowly (sometimes suddenly, and by fits and starts) escape, 

 so that the fluid becomes dark-red, the corpuscles at the same 

 time losing their colour, and acquiring the aspect of colour- 

 less vesicles or rings, so faint, that it is often difficult to per- 

 ceive them. But by the addition of tincture of iodine, which 

 colours them yellow, or of salts (common salt, nitre, &c), of 

 gallic or chromic acid, which cause them to shrink, and to 

 present a more defined outline, they may be readily brought 

 into view ; and it is thus satisfactorily shown that water, by no 

 means dissolves, or destroys them. Some blood-globules 

 always withstand the influence of the water for a longer time, 

 and are still coloured when all the rest have lost their colour- 

 ing matter ; but it is not yet ascertained, whether these are to 

 be regarded as of younger formation, as is commonly supposed, 

 or of older. The latter notion seems to be favoured by the 



