366 Proceedings of Roycd Society of Edinburgh. [sess. 
(e) When diluted with four volumes, opalescence begins at 
81°*5 C., and coagulation 84 0, 75 C. 
(/) When diluted with five volumes, opalescence begins at 82° C., 
and coagulation at 85°'25 C. 
The numbers quoted do not give us the correct coagulation points 
for diluted solutions of serum albumen ; they are the coagulation 
points of diluted solutions plus magnesium sulphate, which raises 
the coagulation point considerably, as we shall subsequently see. 
The experiment only serves to show how coagulation varies with 
dilution of the albumen. In this experiment fine flocculi appeared 
even in the more dilute solutions, and their presence rendered the 
determination of the coagulation point quite easy, even in the most 
dilute solutions. 
In order to determine the action of magnesium sulphate, serum 
albumen was prepared in another way. 
Blood serum was diluted with two volumes of water, and a stream 
of carbon dioxide passed through it. The precipitate of globulin 
was filtered off. By this method the albumen was obtained mixed 
with a small quantity of globulin ; its presence, however, did not 
prevent the recognition of the point of opalescence and the coagula- 
tion point of the albumen. 
(a) The serum albumen became opalescent at 70° C., and coagu- 
lated in flocculi at 74° '25 C. The coagulation point being raised 
two or three degrees above the figure given by Hoppe-Seyler on 
account of its dilution. 
(b) This solution of serum albumen, diluted with one volume of 
water, became opalescent at 74°, the opalescence becoming very 
dense at 78° C. No flocculi appeared. 
On comparing these figures with those given for serum albumens 
in a saturated solution of magnesium sulphate, it will be seen that 
the former are uniformly lower, the presence of magnesium sulphate 
tending to elevate the coagulation point. The effect of dilution is 
more marked in the case of serum albumen by itself than in that of 
serum albumen in the saturated magnesium sulphate solution. In 
the first place, the coagulation becomes very imperfect in the dilute 
solutions ; in the second place, the temperature in the dilute solution 
is very much raised. 
