
size. 
Jone 23, 1923] 
NATURE 
843 

state) we are merely reducing the material to particles 
of molecular dimensions and separated by distances 
beyond each other's sphere of molecular attraction. 
Whereas in ordinary grinding the same action is 
ormed but the particles remain of considerable 
It follows from this that a homogeneous 
crystalline substance such as the diamond—which 
requires a large amount of heat and a high tempera- 
ture to gasify—would be expected to require the 
expenditure of more work in reducing it to a certain 
fine state of division than a substance like ice (sup- 
posed kept at a temperature below freezing-point of 
water), which can be comparatively easily gasified. 
This aspect obviously opens out a large field of 
research until now quite untouched; for example, 


@ 
@ 
2, 
Cc 
D 
Fic. t. 
there exists a large number of organic crystalline com- 
pounds of which the heats of volatilisation are known, 
and the action of which under percussion or pressure 
could be investigated from this point of view. 
The research work carried out has already pro- 
ceeded sufficiently far to allow one to hope that in 
the near future the art of “ grinding” will be trans- 
ferred from its present chaotic state of empiricism 
into that of an exact science. The importance of 
this development in the gold- mining, pigment, and 
other industries—which depend so largely upon the 
production of materials in a state of fine division— 
will be apparent when we reflect on the great advances 
which occurred in the electrical and steam engineering 
sciences when the underlying laws were worked out. 
CHARLES E. BLyTH. 
GEOFFREY MARTIN. 
HAROLD TONGUE, 
The British Portland Cement Research Association, 
Rosherville Court, Burch Road, Gravesend, 
May 30. 

Adsorption and Hemoglobin. 
One fundamental difficulty in the hypothesis that 
oxygen and carbon monoxide are ‘‘ adsorbed” by 
hemoglobin lies in the highly specific nature of the 
. absorption spectrum of the compounds so formed. 
The change in colour of reduced blood, or of a dilute 
solution of reduced hemoglobin, when shaken with 
air or oxygen, is very obvious to the naked eye, as 
also is the change when the oxygen is replaced b 
carbon monoxide. These colour changes can be wea 
either as in Haldane’s method with direct vision, or 
NO. 2799, VOL, 111] 
as in Hartridge’s by the spectroscope, for the exact 
quantitative measurement of the amount of gas 
taken up. Such remarkable, definite, and highly 
specific changes in the absorption spectra have no 
parallel, so far as I am aware, in any well-authenti- 
cated case of adsorption (unless the phenomena of 
electrolytic dissociation be classed as such), and must 
be explained by any theory, as of course they are by 
that of a specific chemical change in the nature of 
hemoglobin by its combination with gas. 
Sir William Bayliss, in his letter to Nature of 
May 19, p. 666, and elsewhere, argues that the 
“widely divergent results obtained by different 
investigators of the heat of combination between 
oxygen and hemoglobin ”’ have not been adequately 
explained. The explanation really is simple, experi- 
mental error. If the solutions, or the blood, be 
reasonably aseptic, if due attention be paid to the 
carbon dioxide driven off when oxygen passes in, 
and if the observations be made with sufficient care 
and criticism, divergent results are not obtained. Any 
theory can be confused by imperfect experiments. 
Again, Sir William Bayliss states that “in con- 
nexion with the relations between hemoglobin and 
carbon dioxide, no proof has yet been given that the 
union is of a different nature from that with oxygen.” 
Several such proofs exist: (a) it can be shown that 
nearly all, if not all, of the CO, taken up by blood 
at small CO, pressures (i.e. within the ‘“ physio- 
logical’’ range) exists there as actual bicarbonate 
(HCO’;) ions; no other reasonable explanation is 
possible of the manner in which the hydrogen ion 
concentration of blood varies with CQO, pressure ; 
-(b) the reaction of blood with CO,, over the same 
range of CO, pressures, produces no change whatever 
in its absorption spectrum ; (c) as the CO, pressure 
is increased the amount of CO, taken up does not 
approach a maximum in the same definite manner 
as does the amount of oxygen when the pressure of 
the latter is increased; neither is there any such, 
precise relation between the Fe and the CO, as 
between the Fe and the O, or CO; (d) the effect of 
CO, on the hemoglobin-CO: reaction is precisely equal 
to that of a change of hydrogen ion concentration, 
exactly equal to that produced by the CO, but set 
up by another acid, such as HCl; in other words, 
the total effect of CO, on the hemoglobin-CO reaction 
is exactly equal to that due to its acid character, 
which leaves no margin at all for any specific effect 
of CO, in turning out CO; in contrast to this, the 
considerable effect of oxygen on the same reaction is 
certainly not due to any change of hydrogen ion 
concentration produced by the oxygen, for (provided 
the hemoglobin be kept saturated with CO and O,) 
this change is nil; (e) the effects (i.) of oxygen and 
(ii.) of CO, on the combination of hemoglobin with 
carbon monoxide are quantitatively quite different ; 
(f) the effects of carbon monoxide on the reactions of 
hemoglobin (i.) with oxygen and (ii.) with CO, are 
also different. 
Sir William Bayliss affirms that “sometimes . . 
workers are so convinced that the mass action view 
is all that is necessary, that they are not interested 
in testing the truth of the assumption.” I can 
assure him that at least ten active workers of my 
personal acquaintance are “‘ sometimes ”’ very much 
interested, and indeed have recently applied the most 
stringent and searching tests to the view that the 
combinations of hemoglobin with oxygen and carbon 
monoxide are. in the ordinary sense of the word, 
chemical, and obey the usual laws of chemistry. 
The accepted manner of “ testing the truth of an 
assumption ”’ is to make theoretical (and preferably 
quantitative) deductions from it, and then to see if, 
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