258 Proceedings of Royal Society of Edinburgh. [sess. 
That is to say, first of all, there is a removal of the excess of 
syntonin, and then after very prolonged action, a splitting up 
of the paranuclein occurs, shown by the fall in percentage of 
phosphorus. 
Trypsin rapidly splits up this paranuclein. 
Both after prolonged peptic and short tryptic digestion, a 
proteid precipitating body is present in the soluble products of 
digestion. In order to compare this syntonin-paranuclein with 
the natural ones, I examined one of the latter, namely, the para- 
nuclein of ovovitellin. It contains about 5 per cent, phosphorus, 
and is moderately resistant to action of pepsin, but is easily split 
up on tryptic digestion, or from action of weak alkalies. In all 
these points it agrees with the syntonic paranuclein. 
We may call the organic phosphorus-holding acid, which is split 
off from this paranuclein by the action of weak alkalies, para- 
nucleic acid. It is distinguished — 
First, by its great solubility in cold water ; 
Second, by its proteid precipitating property ; 
Third, by the absence of nuclein bases among its decomposition 
products ; 
Fourth, by the absence of any reaction with Millon’s reagent; 
Fifth, by its high phosphorus percentage, 7*97 ; 
Sixth, by the absence of all reactions common to proteids, with 
the exception of the biuret, which it gives most distinctly. 
I have, in conclusion, to thank Professor Kossel of Marburg for 
his never- varying kindness, attention, and help in difficulties ; and 
especially to Professor Rutherford, who, during my tenure of the 
Crichton Research Scholarship in Physiology, did everything in 
his power to assist me with my work. 
A grant of £30, which I received from the Dickson Travelling 
Fund, was of great assistance in allowing me to carry on a research 
which I was exceedingly anxious to complete. 
