THE ALBUMINOIDS. 69 
If the iron is, as it appears fco be, in organic union, the nucleins that 
contain it must be anion-- the most complex of known organic compounds, 
consisting of seven elements. 
The exact method in which the iron is combined is however, like the 
constitution of nuclein, still unknown. 
Zaleski ' has succeeded in separating from the liver one of these iron-con- 
taining nucleins, which he terms hepatin. The subject has been largely worked 
by microchemical methods for the detection of iron ; and the terms - firmly 
combined" and "loosely combined" iron are often used, according as the com- 
pounds which contain that element give the reactions with difficulty or ease. 
Macallum 2 finds that the chromatin of nuclei contains iron; he regards 
it as the mother substance of haemoglobin, both in embryological develop- 
ment and during nutrition in extra-uterine life. He finds similar haematogens 
in plants, as did also Bunge. 
Lecith - albumins. — Iiebermann 3 has given the name lecith-albu- 
mins to certain compounds of lecithin and proteid which he obtained from 
the kidney, gastric mucous membrane, lungs, spleen, and liver. The 
lecithin is not removable from these compounds by simple extraction 
with alcohol and ether. These, however, can hardly he considered to 
he immediate constituents of the cells, as they are obtained after sub- 
jecting them to a very severe process, namely, artificial gastric digestion. 
They yield no phosphoric acid and no xanthine bases on decomposition. 
According to their discoverer, they play an important part (in virtue of 
the acidity which they possess in common with nuclein compounds) in 
the separation of the hydrochloric acid of the gastric juice, and in decom- 
posing the alkaline salts of the blood plasma, so as to yield the acid 
salts of the urine. Much more extended investigations are needed, 
however, before important functions like these can be safely attributed 
to them. 
We have already seen that vitellin is a proteid which by some is 
regarded as a globulin, by others as a nucleo-proteid. Hoppe-Seyler 4 was 
inclined to regard the phosphorus found in it as due to a combination 
with lecithin, whereas Hammarsten looks upon some forms of vitellin as 
phospho-gluco-proteids. Xo doubt, vitellin is a name which covers a 
number of different substances; the substance Hoppe-Seyler worked 
with contained as much as 25 per cent, of lecithin. In those cases 
where the phosphorus is present as a nuclein, the nuclein obtained by 
gastric digestion is of the pseudo-nuclein variety. 
The Albuminoids. 
The albuminoids form a heterogeneous group of substances allied to 
the proteids, but differing from them by certain marked characteristics. 
As a rule, they are found in skeletal and epidermal structures, and 
usually they are remarkable for their resistance to reagents. They 
1 Ztschr. f. pkysiol. C'hcm., Strassburg, Bd. x. S. 453 ; xiv. S. 274 ; Ohem. Centr.-BL, 
Leipzig, 1888, S. 759. See also Quincke, Deutsches Arch. f. Mm. 3fed., Leipzig, Bd. xxv. 
S. 567"; xxvii. S. 202 ; xxxiii. S. 23 ; Peters, ibid., Bd. xxxii. S. 182. 
2 Macallum's most recent papers are in Joum. Physiol., Cambridge and London, 1894, 
vol. xvi. p. 268 ; Proe. Roy. Soc. London, 1895, vol. lvii. p. 261 ; 1. 277 ; Quart. Joum. 
Mirr. Se., London, 1896, vol. xxxviii. p. 175 ; Pep. Brit. Assoc. Adv. Sc, London, 1896. 
3 Arch. f. d. ges. Physio/., Bonn, Bde. 1. and liv. 
4 "Med. ehein, Uiitersucb.,'' 1868; Ztschr. /'. physiol. Chem., Strassburg, Bd. xiii. S. 
479. 
