CONDITION 01 If. !■ MOGL OB IN IN CORPUSCLES. 1 8 9 
is generally the case, 1 he w hole of the water contained in the blood would 
not suffice to dissolve the haemoglobin stored up in the coloured 
corpuscles. 
That the haemoglobin is not contained in the blood corpuscles in the 
form nf infinitely minute crystals, is proved by examining the corpuscles 
between crossed Nicols, when they are found not to be doubly refract- 
ing; whilst crystals of haemoglobin, even when reduced to a state of most 
minute subdivision, arc so. 1 
Furthermore, no crystalline or granular structure can be discovered 
when the coloured corpuscles are examined with the highest powers of 
the microscope. 
The assumption was made by Preyer, 2 that haemoglobin exists in the 
corpuscles in combination with potassium, alkaline solutions possessing the 
property of dissolving much larger quantities of haemoglobin than pure water, 
and potassium being the most abundant of the mineral constituents of the 
coloured corpuscles of man, though by no means of all animals* But, as a 
matter of fact, the coloured blood corpuscles do not behave as if they contained 
free haemoglobin in a solid condition, or in solution, or a solution of an alkaline 
compound of haemoglobin. Only one proof of this statement need be given in 
this place, others being adduced when discussing the remarkable, and, as it 
appears to me, untenable proposition of Hoppe-Seyler, that the blood-colouring 
matter, as it exists in the living corpuscles, differs remarkably in properties from 
haemoglobin, so that it should be distinguished by a separate name or names. 
The one proof to which reference is made is furnished by the fact that the 
colouring matter of the red corpuscles is not extracted from them by the plasma, 
or serum, or by fairly concentrated solution of neutral salts, as would be the 
case if they contained free haemoglobin, or an alkaline compound of that 
substance. 4 To explain the fact that haemoglobin is retained by the corpuscles, 
lloppe-Seyler advanced the plausible hypothesis, that it exists in them in 
combination with some constituent of the stroma, and he expressed the opinion 
that this constituent is lecithin. There are absolutely no grounds for the 
latter assumption ; and it has indeed yet to be proved that the phosphorus-con- 
taining principle of the stroma of the coloured corpuscles is lecithin and not 
protagon, as had been very positively asserted by Hermann."' 
Without attempting to speculate beyond the facts which we possess, 
it may, however, be assumed that haemoglobin exists in the blood 
corpuscles in the form of a compound with a yet unknown constituent 
of the corpuscle. This compound, the existence of which we are forced 
to assume, is characterised by remarkable instability, for it is decomposed, 
setting free the haemoglobin, which then passes into solution — (1) when 
the blood plasma or serum, in which the corpuscles are suspended, is 
diluted ; (2) when certain substances act upon the corpuscles (ether, 
chloroform, salts of the bile acids, certain products of putrefaction) ; 
(3) by the action of heat ; by alternate freezing and thawing : by induction 
shocks, etc. 
1 W. Preyer, "Die Blutkrystalle," Jena, 1871, S. 28. 
- Ibid., S. 30-33. 
3 G. Bunge, " Zur quantitative!] Analyse des Blutes," Ztschr. f. Biol., Munchen, 1876, 
Bd. xii. S. 191. 
4 This is no real proof that haemoglobin is not in solution ; it is merely a statement of 
the fact that it is indiflusible through the unaltered envelope of the corpuscle. It is, 
moreover, capable of proof that the contents of the red corpuscles are completely fluid 
during life. Cf. p. 193, lines 9 to 12. — Editor. 
5 Arch. f. Anat. u. Physiol., Leipzig, 1866, S. 33. 
