130 ROLLESTON, ON NUCLEATION OF BLOOD-CELLS. 
It is different enough from that described by Dr. Roberts 
in the Royal Society’s ‘ Proceedings,’ March 19th, 1863, as 
produced in mammalian blood-cells by the action of tannin ; 
but, on repeating his experiment, I satisfied myself that the 
two sets of cases had this in common, viz., that they show 
that the homogeneous coloured mammalian blood-cells may 
be separated into two parts—one colourless and the other 
coloured—of which the latter shall occupy the smaller area. 
I am inclined to think that the elephant’s blood, though 
not fresh, still gave better opportunities for judging of the 
real nature of the appearance of nucleation than dried slides, 
such as those of the sloth’s corpuscles, could give. 
