Blood-cor])uscles of A. tridactylum, &g. By Dr. Schmidt. 65 
specimen of fresh blood, related to a large fragment of a coloured 
blood-corpuscle of the Amphiuma, having the appearance as if it had 
been cut or torn from the rest of the corpuscle (Fig. 14). On this 
fragment the membraneous layer was seen projecting on the torn 
surface. As there was no sharp instrument, nor any force used in 
the manipulation of transferring the blood from the vessel to the 
slide, I am unable to account for the presence of this fragment, 
except in one way, which I shall state farther on. In the blood of 
the Tree-frog I have several times met with coloured blood- 
corpuscles, of which a portion was wanting, as though it had been 
separated by means of a sharp instrument (Fig. 56, c). 
The most interesting and important phenomenon which I 
observed was a fresh blood-corpuscle of the Amphiuma, on which 
the membraneous layer had apparently burst and retracted, leaving 
a portion of the underlying material, the protoplasm, exposed. The 
latter appeared entirely colourless, while the rest, still covered by 
the membraneous layer, exhibited the normal yellow colour of the 
corpuscle. In referring to Fig. 13, representing this specimen, we 
observe at a the colourless, uncovered protoplasm, bordered by only 
a single contour ; while the portions h are coloured, and show the 
same light-greenish border as the uninjured normal blood -cor- 
puscles. A few longitudinal folds, produced by a lateral contraction 
of the corpuscle, will also be noticed. As to the cause, by which in 
this case the membraneous layer might have been torn and the 
underlying protoplasm exposed to view, 'nothing definite can be 
affirmed. I can only explain the rupture of the said layer by a 
spontaneous expansion in a longitudinal direction of the protoplasm 
within ; and that such an expansion does take place sometimes, I 
have actually observed in one case, to be mentioned presently. 
After the rupture has occurred, we may presume that the exposed 
protoplasm will be dissolved in the liquor sanguinis, and that the 
remains of the blood - corpuscle, consisting of the two coloured 
portions, h, continue to circulate until their final disintegration. 
This supposition would at the same time explain the presence of 
those fragments of blood- corpuscles met with in the circulating 
blood, as mentioned before. 
The observation of a rupture of the membraneous layer of the 
coloured blood-corpuscle of the Amphiuma cannot be looked upon 
as other than an important fact, from which some practical 
deductions may be drawn. In the first place, it corroborates the 
existence of a membraneous layer or stratum on the surface of the 
blood-corpuscle, which was already not only indicated by the 
decided greenish border it exhibits, but moreover actually de- 
monstrated by the manifestation of the layer itself in those cases 
above described, where it had become separated from the under- 
lying protoplasm by contraction of the latter. 
