A CTION OF RE A GENTS ON OX 1 r JL EMO GL OB IN 2 o 7 
position of oxyhemoglobin with a rapidity which depends upon their 
conccnlral ion. 
Oxyhemoglobin is soluble in highly diluted alcohol, the solutions 
resisting putrefaction much longer than aqueous solutions. By contact 
with even highly dilute alcohol, crystals of oxyhemoglobin become much 
more sparingly soluble in water. Oxyhemoglobin is insoluble in absolute 
alcohol. When crystallised oxyhemoglobin is treated with a large excess 
of absolute alcohol, it is under favourable circumstances converted into an 
insoluble crystalline modification, to which Nencki and Sieber have 
given the name of parahcemoglobin} This body cannot be looked upon 
as a chemical individual. Oxyhemoglobin is insoluble in chloroform, 
benzol, and carbon disulphide. 
4. Biffumhility. — Oxyhemoglobin offers a remarkable example of a 
soluble crystalline body, which, judged by its power to pass through a 
septum of parchment paper, must be declared to be absolutely 11011- 
diffusible. This character depends upon the enormous size of its 
molecule. 
Comparison of the action of certain reagents on solutions of 
oxyhemoglobin and on solutions of albuminous bodies. — It has 
already been incidentally stated that in hemoglobin an iron-containing 
body is linked to an albuminous body or bodies, and reference has been 
made to the fact that, under the action of various agents, oxyhemoglobin 
breaks up into the iron-containing hematin, and into albuminous bodies. 
Although the decomposition of hemoglobin and its products will be con- 
sidered in some detail in a future section, it is convenient in this place 
to refer to this point, and to state that when oxyhemoglobin is decom- 
posed so as to yield hematin and albuminous substances, the former 
amounts approximately to 4 per cent, and the latter to 96 per cent, of 
the original hemoglobin. 
Such being the case, it is of particular interest to contrast the 
action of certain reagents on solutions of albuminous bodies, and on 
solutions of oxyhemoglobin. 
Solutions of oxyhemoglobin differ remarkably from solutions of 
albuminous bodies in their behaviour towards a large number of 
reagents. 
As Kiihne pointed out long ago, 2 all those tests for albumin which 
do not immediately bring about a decomposition of oxyhemoglobin, 
furnish a negative result when applied to aqueous solutions of this 
body. Cupric and ferrous sulphates, mercuric chloride, silver nitrate, 
neutral and basic acetates of lead, all of which precipitate albuminous 
solutions, occasion (so long as the body remains undecomposed) no pre- 
cipitate — not even cloudiness — when added to solution of oxyhemo- 
globin. So soon, however, as the red colour of oxyhemoglobin has 
disappeared under the action of any one of the above salts, and the 
brown colour due to hematin has appeared (a result which they all 
sooner or later bring about), the characteristic albuminous precipitates 
appear. 
1 M. Nencki und N. Sieber, " Untersuch. ueber die Blutfarbstoff, " Ber. d. deutsch. 
chem. Oeselhch., Berlin, 1885, Bd. xviii. S. 392 ; M. Nencki und B. Lachowitz, "Ueber das 
Parahamoglobin," ibid., Bd. xviii. S. 2126. The reader is referred for a criticism of Nencki 
and Sieber's researches on parahaemoglobin, to a paper by Hoppe-Seyler, entitled "Ueber 
Blutfarbstoffe und ihre Zersetzungsproducte," Ztsehr. /'. physiol. Chem., Strassburg, 1886, 
Bd. x. S. 531. 
2 "Lehrbuch der physiolog. Chemie," Leipzig, 1866, S. 207. 
