1894.] Chemico-Physiological Discoveries: The Cell. 107 
proteolytic action of the gastric juice,’ which dissolves away the 
excess of proteid matter leaving a non-digestible nuclein. 
The essential points of difference between the typical nucleins 
are made clear by a study of their cleavage products. Thus, 
the nuclein found in the karyoplasm of most cell nuclei on 
being boiled with dilute sulphuric acid, yields as cleavage 
products, phosphoric acid, xanthin bodies and acid-albumin, 
The nuclein, on the other hand, present in the sperm of the 
salmon fails to yield any albuminous matter, its cleavage pro- 
ducts being only phosphoric acid and hypoxanthin. The third 
group of nucleins, better known as nucleo-albumins, yield only 
phosphoric acid and albuminous bodies by cleavage, the 
xanthin bases, if formed, being in too small quantity to admit 
of certain detection. From the nuclein of yeast cells, Lieber- 
mann obtained by cleavage metaphosphoric acid, and both he’ 
and Pohl.were able to prepare a combination of metaphos- 
phoric acid with egg-albumin, also with serum-albumin and 
with albumose, resembling nuclein in properties. Further- 
more, by varying the proportions of acid and albumin it is 
possible to prepare different forms of nuclein, varying in their 
content of phosphorus, and in their solubility in alkalies, like the 
natural nucleins obtainable from cell nuclei. It is questiona- 
ble, however, whether these synthetical products are in every 
way akin to the natural nucleins, for it seems probable that 
the nuclein molecule formed through the activity of the living 
cells is constructed on a somewhat different plan, so far as the 
arrangement of the atoms is concerned. Thus, Altman? has 
shown that when a nuclein is subjected to a mild process of 
decomposition, as on exposure to the action of an alkali at 
ordinary temperature, it is broken apart into albumin and a 
peculiar acid rich in phosphorus, to which the name of nucleic 
acid has been given. Moreover, it is possible to regenerate 
the nuclein out of these two components, the body so recon- 
structed having all the properties of the original substance. 
Nucleins, therefore, to quote Halliburton, may be considered 
€ Compare Lilienfeld Du Bois Reymond’s Archiv f. Physiol. 1892, p. 129. 
‘Liebermann. Pfliiger’s Archiv fiir physiologie Bd. 43 p. 99. 
Ueber Nucleinsiuren. Du Bois Reymond’s Archiv für Physiol, 1889, p. 524. 
