XSri^S^ Blood-corpusde of Ovi^parous Vertebrata. 235 
of nature ? It is merely with a view to indicate the direction our 
future researches on these subjects should assume that the present 
observations are offered. For although new facts may dawn upon 
us, and new triumphs of optical and mechanical skill may hereafter 
enable us to detect subtleties of structure as yet invisible to our 
senses, at the risk of giving utterance to a threadbare truism, I 
would express my faith that every new fact and every additional 
means of observation we may in future command will only serve to 
prove more incontestibly — if further proof be needed — that even in 
her subtlest workings Nature still abides by Law, and permits no 
exceptional case — such as that which has been assumed to take 
place in these lowest forms of life — to disturb her harmony. 
IX. — On the Structure of the Bed Blood-corpuscle of Oviparous 
Vertebrata. By William S. Savory, F.E.S.* 
The red blood-ceU has been perhaps more frequently and fully 
examined than any other animal structure; certainly none has 
evoked such various and even contradictory opinions of its nature. 
But without attempting here any history of these, it may be shortly 
said that amongst the conclusions now, and for a long time past, gene- 
rally accepted, a chief one is that a fundamental distinction exists 
between the red corpuscle of Mammalia and that of the other verte- 
brate classes ; that the red cell of the oviparous vertebrata possesses 
a nucleus which is not to be found in the corpuscle of the other 
class. This great distinction between the classes has of late years 
been over and over again laid down in the strongest and most 
unqualified terms. 
But I venture to ask for a still further examination of this 
important subject. 
As the oviparous red cell is commonly seen, there can be no 
doubt whatever about the existence of a " nucleus " in its interior. 
It is too striking an object to escape any eye ; but I submit that its 
existence is due to the circumstances under which the corpuscle is 
seen, and the mode in which it is prepared for examination. I 
think it can be shown that the so-called nucleus is the result of the 
changes which the substance of the corpuscle undergoes after death, 
and which are usually hastened and exaggerated by exposure, and 
the disturbance to which it is subjected in being mounted for the 
microscope. When a drop of blood is prepared for examination, 
* Througli tlie kindness of Dr. Sharpey, Sec. R. S., we are permitted to repro- 
duce this most important contribution of Mr. Savory's. — Ed. M. M. J. 
VOL. I. S 
