384 Proceedings of Royal Society of Edinburgh. [sess. 
had suggested. They, no doubt, produced coagula, but, had they 
tried the experiment, they would have obtained them equally well 
at a lower temperature provided they had raised the temperature 
more slowly. It is not difficult to fractionate egg albumen ten or 
twelve times. 
Another point that struck us was the smaller and smaller 
amount of coagulation produced, as the temperature of the solution 
was raised and successive crops produced. This was noticed 
by Dr Halliburton in the case of egg albumen. It is certainly the 
case with egg albumen. This, of course, in itself renders it highly 
probable that we are dealing in both cases only with one 
albumen, the more dilute solutions of which are alone coagulated 
at the higher temperatures. Even supposing that the y serum 
albumen of Dr Halliburton, of which he “in some case only 
found a trace,” and which coagulates at 82° C., is different from a 
and /? serum albumen, found in greater quantity, and coagulating 
at lower temperatures, yet fractional coagulation could not give 
us the means of proving this. One cannot compare the coagulating 
points of a dilute with a strong solution of two albumens, and 
presuming that y serum albumen is a dilute solution of an albumen 
differing from a and /?, yet its coagulation point would be lower 
than 82° C. in a solution of corresponding strength. 
It is, of course, possible that serum albumen may consist of more 
than one albumen, although it is probable, from what we have 
brought forward, that all the albuminous matter present coagulates 
at the same degree of concentration — at or about the same tempera- 
ture. Other methods may enable the physiologist to separate 
these, if they exist, from one another, and no methods have in the 
past yielded such valuable results as those in which separation 
has been obtained by the addition of neutral salts. Dr Halliburton 
has by this means tried to separate the a, /3, and.y serum albumens 
from one another, and frankly states that he has failed to do so 
(Reference 6, p. 173). 
In conclusion, we may. state that the method of fractional 
coagulation could only be of service when the coagulation points 
of the albumens present are widely separated from each other. In 
reality, fractional coagulation has been for a long time in use, and 
one of the few cases in which, as far as we can see, it is at all 
