Blood-corpuscles of A. tridactylum, &c. By Dr. Schmidt. 67 
by the irregular manner in wliich the contraction takes place. 
For while in some instances, as in Figs. 3, 4, &c., the contractive 
force seems to extend throughout the whole body of the blood- 
corpuscle either in one or the other direction, in others it appears 
in different points, affecting only separate portions of the protoplasm. 
Thus, wrinkles or folds extending in various directions will be 
produced. Sometimes they appear in the form of pointed projec- 
tions, as processes and spines (Fig. 5) ; at other times the blood- 
, corpuscle becomes constricted at one place, and assumes the form of 
a dumb-bell (Figs. 11 and 12). 
Now, although these contractions of the protoplasm inducing 
those manifold changes in the form of the blood-corpuscles occur 
under the eye of the observer, they nevertheless become imper- 
ceptible, like the movements of the hands of a watch, by the 
gradual and irregular manner in which they take place. In one 
instance (Fig. 11), however, I observed very distinctly the sponta- 
neous motion. This consisted in an expansion of the larger portion 
of the constricted blood-corpuscle (Fig. 11, a) assuming the form as 
represented by the outlines h, and finally recontracting to its former 
form a. This is the only case of spontaneous motion which I ever 
witnessed in the coloured blood-corpuscles of the Amphibia. In 
those of Man I have observed it in a number of instances, to be 
mentioned hereafter. 
When water is applied to the specimen of blood under exami- 
nation, the wrinkles and constrictions of those blood-corpuscles 
which were deformed in various ways by the contraction of their 
protoplasm, gradually disappear, and the corpuscles will be seen 
expanding, in order to resume their original oval form. At the 
same time, however, they are deprived of their colouring matter, 
and rendered colourless by the endosmotic current of the water into 
their interior. 
Besides the phenomena exhibited by the fresh blood-corpuscles 
of the Amphiuma, described above, there are others which, though 
they have been previously observed on the blood-corpuscles of 
other animals, are still interesting enough to be stated in this place. 
They consist in the presence of crystals, and also of vacuoles or 
bubbles of gases in the interior of the corpuscles. As regards the 
crystals, besides Eichardson having observed and described them as 
occurring in the blood-corpuscles of the Menobranchus, I have 
myself at different times met with them in the coloured corpuscles 
of the human embryo. In the latter instance, however, they may 
have formed after death, and by the action of a weak solution of 
chromic acid in which the specimen had been laid ; in Eichardson’s 
case I am unable to state whether the blood was taken from the 
living or dead animal. In the Amphiuma, crystals are met with 
quite frequently in the interior of the coloured corpuscles of blood 
