170 BLOOD. 



several other chemically indifferent bodies, on the form of the 

 corpuscles and the colour of the blood, has certainly been already 

 carefully examined from various points of view, but notwithstand- 

 ing this, the subject still requires a systematic investigation, in 

 order to establish definite relations between the form of the 

 blood-cells and the colour of the blood in connexion with the 

 amount of concentration of the solutions, the temperature, and 

 other external conditions. For the changes which the forms of 

 the blood-corpuscles undergo are not limited merely, according to 

 the laws of diffusion, to a simple spherical expansion, or to a 

 flattening and a deeper central depression, but in blood obtained 

 during disease we very often find flatly-pressed, jagged, indented 

 and granular, or altogether distorted yellow corpuscles, and we 

 also observe similar modifications induced by the artificial addition 

 of various concentrated solutions of chemically indifferent sub- 

 stances. At present, not even an ideal connexion has been esta- 

 blished regarding the influence which the form of these jagged, 

 star- shaped corpuscles or the nummular rolls exert on the colour 

 of the blood; indeed objectively the colour co-existing with such 

 forms has not been sufficiently observed. In reality this only is 

 established, that all substances which dissolve or in any way destroy 

 the investing membrane of the blood-corpuscles, or which cause 

 it to burst, so that their contents become mixed with the inter- 

 cellular fluid, communicate an intensely dark brownish red or 

 almost black colour to the blood ; while, on the other hand, all 

 those which cause a shrivelling of the cells, or a folding or 

 thickening of the investing membrane, give to the blood a lighter 

 red colour, indeed during the first moments of their action almost 

 a vermilion tint. 



Henle was correct in his assertion, that in fresh blood, even 

 when there is no disease, we observe other forms than those usually 

 presented by the blood-corpuscles, and that in some specimens 

 of blood the corpuscles more readily assume a jagged form than in 

 others. This alteration of form is therefore only a consequence of 

 influences which act on the blood submitted to examination ; the 

 predisposition to this change of form varies, however, in different 

 blood, just as the urine in various acute diseases may be earlier or 

 later in assuming its acid character and in depositing crystals of 

 uric acid. All that we know regarding the manner in which the 

 blood-corpuscles become jagged or dentated is, that chloride of 

 sodium often induces a similar change of form in normal blood, 

 and that a great concentration of the intercellular fluid promotes 



