DR. C. A. MAC MUNN ON MYOHSEMATIN AND THE HISTOH2EMATINS. 283 
In those muscles of Bombus which contained the modified myohmmatin, treatment 
with ammonium sulphide developed the second myohtematin band, but that before 
D could not be seen, i.e., all the bands of the four-banded spectrum were present 
except the first. After the muscles of a moth had stood some time in glycerin the 
change into modified myohmmatin also took place, and on treating with ammonium 
sulphide the above-described change took place. 
In Acricla viridissima I found myohsematin present, but as in other orthopterous 
insects it is not present as abundantly as in dipters and lepidopters. On treatment 
with sulphide of ammonium the bands become much more distinct. (For Periplaneta 
and Gryllus see above.) 
The diurnal and nocturnal lepidoptera show abundance of myohsematin in their alar 
muscles, thus in Pieris rdpce, and other butterflies of which several have been 
examined, the spectrum is exactly the same as that described above. In various 
night moths, which need not be enumerated, it is present in abundance, and it also 
occurs in the mouth parts of various larvse. 
I have tried to isolate myohsematin from insect muscle but without result, owing to 
dearth of material. After boiling in water, the solution appeared to have a faint 
bluish fluorescence, due probably to the presence of fine particles in suspension ; and 
the mitscle itself no longer showed the original spectrum but that of modified 
myohsematin described above (except that the original spectrum was not restored with 
NH 4 HS). The action of various solvents was tried in vain. 
Acids cause the bands to disappear. Caustic alkalies (in strong solution) modify 
the spectrum when added to the solid muscle, the band before I) disappears, another 
narrow band appears after D, and the dominant (3rd) band changes, being now made 
up of a lighter part nearer red, and a darker nearer violet; on treatment of the muscle 
(thus treated) with ammonium sulphide no noticeable change takes place. On treating 
the muscle of a moth with acetic acid the bands disappear, and on again adding caustic 
soda the bands appear as they do when caustic soda alone is used. With hydrochloric 
acid the bands also disappear, and on again adding caustic soda the third and fourth 
bands of the normal myohaematin spectrum reappear, the spectrum thus reproduced 
resembling the modified spectrum described above. 
When an attempt is made to mount an insect muscle in Canada balsam, the pre¬ 
liminary treatment destroys the bands, they are not much changed by being placed in 
alcohol, but in oil of cloves the bands completely disappear ; this change is no doubt 
due to the ozonising action of the oil of cloves.'” 
On treating a muscle from a moth’s thorax with peroxide of hydrogen the bands 
disappear, and the muscle is bleached by this treatment. On again treating with a 
reducing agent ( e.g ., sulphide of ammonium) a new spectrum appears, the second and 
* In glycerin, specimens of muscle preserve the banded spectrum of myohaamatin for months, but it 
finally becomes altered into the modified variety. Insect muscle mounted in glycerin jelly soon changes 
as to the spectrum. 
