288 DR. C. A. MAC MUNN OR MYOHAEMATIN AND THE HISTOH2EMATINS. 
Birds. 
So far there is no difference in the spectrum of myohaematin in all the animals 
examined. In birds and mammals the band at D may vary slightly, as will be seen 
when the spectra are described. 
In the pigeon (Columba livid), while the dominant bands of myohaematin are present 
in the ventricle of the heart that at D may be replaced by two ; the same bands are 
seen in the auricle. In the pectorals and some leg muscles the band at D is the same 
as in the above-mentioned species; and in other voluntary muscles—where myohaematin 
occurs generally with oxyhaemoglobin—this band is also similar. 
In the snowy owl (Nictea nivea ) the ventricle shows the usual myohsematin 
spectrum (spectrum 11, Chart IV.), also the auricle. It is present abundantly in the 
pectoral muscles (as it is in all birds),* sparingly in the leg muscles, being apparently 
replaced to a great extent by oxyhaemoglobin. 
In the gizzards of fowls I have found oxyhaemoglobin, whose second band is, 
however, slightly darker than it should be, probably from the presence of a trace of 
myohaematin. 
In the heart of the common fowl the band at D shows frequently the peculiarity 
noted above in the pigeon. Here the myohaematin bands may be measured, and give 
the following result :— 
1st band 
2nd band 
3rd band 
X 613 to X 596'5, and shading X 589 to X 582, 
X 569 ,, X 563, 
X 556 ,, X 550 (approximate), 
and these are well seen in auricle and ventricle. 
In the ventricle of the turkey’s heart the bands read :— 
1st band ... X 613 to X 593 (and shading?), 
2nd band ... X 569 ,, X 563, 
3rd band ... X 556 „ X 550. 
In the auricle oxyhaemoglobin appears to be the dominant pigment. 
In the auricle and ventricle of the goose the bands read :— 
1st band . . . X 613 to X 593, 
2nd band . . . X 569 ,, X 563, 
3rd band . . . X 556 ,, X 550. 
There are also two other bands nearer violet, too faint to be read. In the auricle and 
ventricle of the duck they give the same readings. 
Putting M for myohaematin and H for haemoglobin, the following rough sketch will 
give an idea of the distribution of myohaematin in the voluntary muscles of a bird 
(pigeon): 
* In fact the pectorals of the pigeon are mainly, if not altogether, coloured by myolitematin. 
