361 
1888-89.] Prof. Tait’s Note on Capt. Weirs Paper. 
axis of x, and draw AP parallel to y. Make AOP = X, and yOH = h. 
Draw the circles whose centre is 0, and radii OP and AP respec- 
tively. Let OH meet them in p , q. Prom p and q draw lines 
parallel to 0 y, Ox, respectively. Their point of intersection, Q, 
belongs obviously to the ellipse X, and to the hyperbola h. A 
somewhat similar, simple, construction can easily he given for the 
circle. 
On the Coagulation of Egg and Serum Albumen, 
Vitellin, and Serum Globulin, by Heat. By John 
Berry Haycraft, M.D., D.Sc., and C. W. Duggan, M.B. 
{From the Physiological Laboratory of the University of Edinburgh. ) 
(Read July 15, 1889.) 
A large number of proteid substances, when in solution, are 
coagulable by heat. As the temperature of such a fluid is raised, 
faint opalescence at first appears, and then, at a higher temperature, 
masses (flocculi) of albumen separate out, in most cases, suddenly, 
from the fluid. It is generally held that each coagulable albumen 
is so affected at a definite temperature peculiar to itself ; thus, egg 
albumen is said to become opalescent at 60° C., and to separate out 
in flocculi at 63° C. Unfortunately, hardly two observers agree as 
to the exact temperature at which opalescence and coagulation 
