42 
Br. BealEj on the Red Blood-corpuscle, 
puscles differing very much from the ordinary red corpuscles 
in size^ colour^ and refractive power. They are much smaller 
than the latter; they exhibit a granular appearance^ and are 
colourless. They might be described as small white corpus- 
cles^ but many are much smoother than the colourless cor- 
puscles. It is not easy to see these corpuscles unless the 
blood is examined by powers magnifying upwards of 1000 
diameters. Such corpuscles are exceedingly faint and can 
only be distinguished if great care be employed. I believe 
that corpuscles exist v/hich are so very transparent as not to be 
visible. The small^ faintly granular corpuscles are coloured by 
the carmine solution^ but the ordinary red blood-corpuscles, 
like the external coloured portion of the frog^s blood-corpus- 
cle, is not coloured. 
These blood-corpuscles are probably young ones, the germi- 
nal matter of which has only just commenced to undergo 
conversion into the red formed material. In some cases I 
have seen a delicately granular, colourless material protruding 
from a small coloured corpuscle. From the appearance, there 
can be little doubt that the living matter had separated from 
the coloured formed matter (PI. VII, fig. 10). This colour- 
less material I regard as the germinal matter of a young cor- 
puscle, and think it probable that some of the appearances 
which have been delineated by Dr. Eoberts result from the 
action of the solutions employed upon a small quantity of 
this granular germinal matter. 
The red corpuscles vary in size much more than is usually 
supposed, and they differ very much in transparency and 
refractive power, some being only just visible, in consequence 
of the extreme transparency of the material of which they 
are composed. Some are actually invisible ; but when sur- 
rounded by red corpuscles, their presence is proved by the 
grouping of the red corpuscles around what appears as a cir- 
cular clear space (PL VI, fig. 8) . After such corpuscles have 
remained still for some time, slight fissures may be seen con- 
verging in straight lines towards the corpuscle. I believe 
these to be channels made by the flowing of nutrient pabulum 
towards the corpuscle. This fact proves that the young and 
colourless, or nearly colourless, corpuscles absorb nutrient 
material after removal from the body, which is not taken up 
by the red corpuscles, between which it flows; so that I am 
led to the conclusion that the red corpuscle exists first 
as a very small spherical mass of transparent, colourless, 
germinal matter, which continues to grow for a time, and 
gradually undergoes conversion into the red colouring matter, 
which corresponds to the formed material of cells generally, 
