PRESIDENTIAL ADDRESS 
ON 
SURFACE-FILMS 
By W. RAMSDEN, M.A., D.M., 
Professor of Bio-Chemistry at the University of Liverpool. 
{Read to the Society, 18th October, 1918] 
Some years ago I observed a very remarkable 
phenomenon in diluted white of egg, and it has seemed to 
me that it would be useful to the members of this Society 
to hear an account of it and of the observations to which 
it led, since this would serve as an introduction to the 
consideration of various surface-phenomena of much 
_ importance for the biological and medical sciences, and 
would also give me an opportunity to bring forward certain 
_ views which, although not found in the text-books, appear 
to me indispensable for the interpretation of the faets. I 
have not thought it necessary for the purpose of this 
address to indicate to what extent these views are novel. 
MECHANICAL SURFACE-AGGREGATES. 
On pouring a dilute filtered solution of white of egg 
repeatedly to and fro from one test-tube into another a 
very extraordinary thing happens—numerous loose fibrin- 
like solid flakes develop in the liquid. They consist of 
coagulated protein, and are permanently insoluble in the 
_ mother-liquid. They are formed also when the solution 
is vigorously shaken up in a closed vessel, although they 
are then easily overlooked because they are mostly 
entangled in the froth. It is even possible by prolonged 
shaking of the solution to convert the whole of its 
edagulable protein into insoluble solid. 
