36 Dr. Beale_, on the Red Blood-corpuscle, 
physical and cliemical changes alone. But those who argue 
in this way have never been able to produce artificially cells 
which could not be distinguished from those formed in living 
structures ; and the existence of the most important and only 
vitally active part of the cells has been by some altogether 
ignored. Many observers who have admitted its existence 
have regarded it as the least important part of the cell (see 
Huxley^s views on the cell) . 
Ifc may be possible to produce, artificially, coloured bi- 
concave, circular, or oval discs, like the red blood- corpuscles ; 
but I am confident that the colourless nucleus of the oval 
corpuscle and the white corpuscles cannot be produced except 
in the body of a living animal, for this colourless material has 
very remarkable properties, which do not exist in connection 
with any lifeless matter known. 
I would consider frog^s blood-corpuscles as consisting simply 
of {a) a mass of colourless, living, or germinal matter within, 
which is surrounded by (b) the coloured formed material. 
Like other kinds of germinal matter, the ^' nucleus of the 
oval blood-corpuscle, and of the young mammalian blood-cor- 
puscle, and the ordinary colourless blood-corpuscles in ail 
animals, as well as very small ones having the same general 
characters, are coloured red by an alkaline solution of carmine. 
On the other hand, the fully formed mammalian red blood-cor- 
puscle and the coloured part of the frog^s corpuscle are not 
coloured by this reagent. That a cell-wall is a necessary 
structure or essential to the being of what we call a red blood- 
corpuscle, I think is distinctly disproved by the following 
facts : 
Facts incompatible with the existence of a membranous en- 
velope possessing properties and composition distinct from 
the coloured contents. 
1. I have seen corpuscles change form under the micro- 
scope, as represented in PI. VI, fig. 1. This was not due to 
pressure, because there were other corpuscles close to these of 
the usual form. It seemed to me that the phenomenon was 
easily explained upon the supposition that the mass was com- 
posed of matter of the consistence of treacle, and it is not 
possible to conceive that portions could be detached in the 
manner represented, if a membranous cell-wall exists. 
By the application of a gentle heat, about 100°, similar 
changes may generally be produced (fig. 3). It seems as if 
the viscid material of which the blood-corpuscle is composed 
became, in the first instance, more fluid ; and then, as the slide 
