TRANSACTIONS OF SECTION I. resi, 
3. Some Observations on Blood Pigments. By P. P. Larpiaw, B.A. 
Hoppe-Seyler was the first to notice that iron in hemochromogen was unstable 
to dilute acids, but his statements were contradicted by other observers. 
There is, however, no doubt on the subject, as is very easily demonstrated ; not 
only so, but reduced hemoglobin presents the same peculiar instability of iron, 
yielding hzematoporphyrin to diluted HCl in the cold without heat. The fact 
that oxygen renders the iron stable in oxy-pigments indicates that it is in relation 
to the iron. 
The instability of the iron in hemochromogen shows that hematoporphyrin is 
present in the hematin molecule, and is not a product of intramolecular change. 
This is absolutely proved from the fact that hematin may be reformed from 
heematoporphyrin. 
Tron-free hematoporphyrin is warmed in ammoniacal solution on the water- 
bath, and Stokes’ fluid added ; on repeatedly reducing the mixture for an hour or 
so, hteemochromogen is formed. The spectroscopic characters are identical in the 
natural and artiticial pigments. If pure pigment is used hydrazine hydrate is 
required to effect reduction to hemochromogen in both, and in the presence of 
blood proteids ammonium sulphide is efficient in both natural and reformed 
hematin. ‘The method of synthesis and the percentage of iron render it probable 
that hematin does not contain an acetyl group, but that it is a combination 
of two hematoporphyrin groups with one of iron. 
The incineration tigure for iron appears to be a little less than 1 per cent., iden- 
tical with that calculated for acompound of this sort. Compare Nencki’s views on 
the point. 
Turacin, the naturally occurring pigment in the wing feathers of some of the 
plantain eaters, may be obtained from hematoporphyrin by boiling with cupram- 
monium solutions. 
The spectra and physical characters are identical in natural and artificial pig- 
ments; both contain rather more than 7 per cent. of Cu. 
A cobalt compound of hematoporphyrin may be obtained by boiling ammo- 
niacal solutions of heematoporphyrin and corbaltamine. This substance presents 
absorption bands in the same place as oxyhemoglobin, and will reduce to the 
spectrum of reduced hemoglobin. 
Bilirubin will not form an iron compound on the lines of the above hematin 
synthesis, but what I believe to be a copper compound is obtainable by boiling 
with cuprammonium solution, a green pigment changing to intense blue-purple 
on acidification. This may be used as a test for bile pigment. The solutions in 
acid and acid chloroform have characteristic spectra. 
4. On the Distribution of Potassium in Animal and Veyetable Cells. 
By Professor A. B. Macattum, Ph.D. 
The continuation of the investigation on the distribution of potassium in cells 
has furnished the following results :— 
1. Potassium is never diffused throughout protoplasm, but is always localised, 
either in the condition of a solution or in the form of a precipitate in what appears 
to be inert material. 
2, It is always more abundant in vegetable than in animal protoplasm. The 
preponderance in the former is due to the greater accession of the element to 
vegetable structures, in solution in sap and other currents, and to the precipitation 
in the protoplasm of the potassium so carried which is thus rendered inert. 
3. The nucleus is absolutely free from it, and so also are structures of nuclear 
origin (heads of spermatozoids, animal and vegetable), as well as the ‘central 
body’ of the cyanophyceze, which is regarded by some cytologists as a nucleus. 
4, Only one tissue element, the nerve cell and the axis cylinder (the neuron), 
