DR. C. A. MACMUNN ON MYOHAEMATIN AND THE HISTOHHCMATINS. 295 
vations are of value in helping to decide a difficult point. I have not succeeded yet 
in finding out whether these pigments are dissolved in the plasma bathing the tissues, 
or in the solid parts of the tissues. In the case of muscle, certainly a small amount of 
myohsematin was obtained from the plasma, but after squeezing out all juice, the 
muscular fibre showed abundance of myohsematin, which at the same time may have 
been prevented exuding by coagulation of the myosin. I am inclined to believe that a 
certain amount of myoheematin belongs to the solid (or semi-solid) part of the muscular 
fibre, and probably the same remark applies to muscle haemoglobin ; for after all the 
opposite conclusion is mainly based on Kuhne and Eberth’s observation of the 
presence of a living nematode within the sarcolemma, and this does not altogether 
exclude the possibility of the presence of a colouring matter in the sarcous substance. 
I have not insisted strongly on the fact that myohaematin is a histohsematin, as 
auyone cannot fail to come to that conclusion who studies the accompanying charts. 
Myohsematin then may be considered as the true intrinsic colouring matter of muscle, 
and the histohaematins the intrinsic colouring matters of the tissues and organs; both 
may be reinforced or replaced at times by haemoglobin when extra activity of internal 
respiration is required ; probably the same radical may be made use of for building up 
all these pigments, at all events they seem to be related, since the same decomposition 
product—hsematoporphyrin—is probably yielded by all of them. The fact that in the 
lower animals pigments of less complex molecular structure than haemoglobin and 
identical with its decomposition products can function like it, forces itself on anyone’s 
attention who studies the pigments of the Invertebrata. 
Lastly, I would call attention to another striking fact which I have found out, 
thanks to Professor Moseley. In his most valuable Paper # on “ animal colouring 
matters,” which he discovered while on board the “ Challenger,” he describes a madder- 
coloured pigment named by him polyperythrin, and he suggested that it might have 
some connexion with some of the pigments found by me in Actinice .t It was found 
by Professor Moseley in simple stony corals of very different genera, in two forms of 
Actiniae from deep water, and in certain hyclroids. In the drawing accompanying 
Professor Moseley’s Paper he figures an acid and an alkaline spectrum, and it will be 
noticed how these spectra resemble acid and alkaline hsematoporphyrin respectively. 
On examining some slides of the dried pigment kindly sent by Professor Moseley, I 
found that the bands of the neutral dried pigment corresponded very closely (although 
not exactly) to those seen in artificially-prepared neutral hsematoporphyrin, and in 
that obtained from the integument of Ur aster rubens, &c., and still mors closely to 
the bands in the egg-shell of a Cochin China hen.| Moreover, with good illumination, 
* “ On the Colouring Matters of Various Animals,” &c., Quart. Journ. Micros. Soc,, vol. xvii., N.S., 
pp. 1-23. 
| “ Chromatology of Actinias,” Phil. Trans., vol. 176, p. 641. 
f In which, as in many other birds’ shells, hsematoporphyrin occurs as such. For a list of the 
animals in which polyperythrin was found, see Professor Moseley’s Paper, loc. cit. [Since the above was 
