292 DR. C. A. MAC MUNN ON MYOHyEMATIN AND THE HISTOHJEMATINS. 
they reappeared. Acetic acid did not seem to affect them. On examining the 
muscle thus treated I could still see a trace of the band before D, but the others 
had disappeared. 
Some of the filtered pepsine extract was evaporated to dryness on the water-bath 
and left a yellowisli-red, amorphous residue. This was insoluble in alcohol or chloro¬ 
form (which each removed a trace of lutein, and other matters, but not the pigment), 
in benzol and light petroleum, but it easily went into distilled water, forming a yellow 
solution and giving the bands referred to above, and with sulphide of ammonium the 
bands were intensified (spectrum 18 , Chart IV.), and read :— 
1st band ... A 554 - 5 to A 548 - 5, 
2nd band ... A 524\5 ,, A 519. 
There still remained in the dish traces of a purplish-brown pigment, which was 
probably changed myohoematin, from the reaction obtained with it. By the use of 
trypsin digestion I failed to isolate the same pigment. 
I succeeded in isolating the same pigment from the pectoral muscle of a pigeon, and 
got the above results. Hence any attempt at isolation alters the nature of the pig¬ 
ment, except freezing. But we may so far conclude that myhosematin is a yellow or 
reddish-yellow pigment, and when isolated and changed soluble only in water. 
I hope to continue these experiments shortly. 
The ITcemochromogen of the Medulla of the Adrenals and the Pathology of 
Addison’s Disease. 
In the adrenals, as already shown, we meet with a spectrum which is totally 
different from that of the histohsematins, for while in their cortex a histohaematin may 
be present, in the medulla jfree hsemochromogen occurs. A similar spectrum may be met 
with occasionally in the liver, and perhaps in the spleen. Its bands are certainly 
diminished after the injection of salt solution, hence here the hsemochromogen must be 
looked upon as an excretion. This spectrum is very constant, and so far I have found 
it in the adrenals of man, dog, cat, rabbit, rat, guinea-pig, ox, and sheep. Vulpian 
has shown that taurocholic acid exists in the medulla,* and other observers have found 
products which indicate the existence of an active downward metabolism. Taken in 
connexion with my own observations these facts go to prove that the adrenals are organs 
which are concerned in the retrogressive metamorphosis of haemoglobin, and probably 
of the pigments described in this paper—the histohsematins and myohsematin. Hence 
if the adrenals are not in a fit state for the discharge of their functions we may 
have pigments present in the circulation which are incompletely metabolised. Now, I 
have shown that such is the case, as the urine of Addison’s disease may contain a 
* Other constituents are leucin, hypoxanthin, benzoic and hippuric acids, taurin, &c. 
