98 PROF. GULLIVER ON THE RED CORPUSCLES [Feb. 25, 
Birds.—The vesicle, when treated with water, so far from retaining 
its shape or becoming narrower, as erroneously represented by Pro- 
fessor KGlliker, becomes generally more or less round in this and the 
lower classes ; and so do the oval corpuscles of the camels. 
No hird has yet been found with the majority of the corpuscles 
otherwise than oval. In any drop of blood a few of them may be 
more or less circular; but their most common figure is with the 
short diameter as 1 to the long diameter between 14 and 2. Still 
they vary in different species, so as to present the form of a broader 
or narrower ellipse. The broad short shape is frequent in some 
little granivorous and insectivorous birds, as the Rice-bird; and 
the narrow long shape in several birds of different orders, as the 
Snowy Owl, Passenger Pigeon, and Butcher-bird. The thickness 
of the corpuscle is between a third and a fourth of its short dia- 
meter. 
As might be expected from their comparative uniformity of organi- 
zation, in birds the size of the corpuscle is much less variable than 
in Mammalia, and has throughout the class so far more relation to 
the size of the species, whether of one or different orders, that Hew- 
son would scarcely have said of this class that the corpuscles are not 
disposed to be larger in the large than in the small species. In 
short, no instance is yet known, ceteris paribus, of a prevalence of 
the largest corpuscles in the small and the smallest corpuscles in the 
large birds, taking a great number of the different-sized species to 
compensate for aberrations ; so that the whole class resembles in this 
respect a single order of Mammalia, and is alike without an exact or 
regular gradation in the size of the corpuscles, the rule applying 
only with many exceptions, as before noticed or implied. The Horn- 
bill, for example, has larger corpuscles than some much larger birds, 
as the Pelican. 
A very remarkable relation exists between the short diameter of 
the oval corpuscles of birds and the diameter of the circular cor- 
puscles of Mammalia. Indeed, so constant is this coincidence that 
it may be accepted as arule. I have not met with an example in 
which the breadth of a bird’s corpuscle does not closely correspond 
to the diameter of the corpuscle of some of the Mammalia. 
Reptiles.—In structure and shape the corpuscles of reptiles are 
the same as in birds; but in size the reptilian corpuscles vary so 
greatly as to afford a remarkable contrast in this respect with birds. 
The largest occur in the naked amphibia, especially in the perenni- 
branchiate subdivision, as discovered by Professor Wagner; and 
the smallest in the lizards, tortoises, and serpents. Such is their 
magnitude in the Proteus, that they may be seen with a common 
hand-lens; and the observation of Dr. Crisp, which accords with 
my subsequent examinations of them in the fresh blood, shows that 
they are nearly as large in the great Japanese Salamander. In that 
paradoxical creature Lepidosiren, I found that the corpuscles have the 
true reptilian character, being larger than those yet known of any 
fish, and having also a stronger and more durable vesicle than that 
of the blood-corpuscle generally of fishes; and Dr. Gray (a very 
