Blood-corpuscles of A. tridaciylum, &c. Bij Dr. Schmidt. 77 
perfectly discoloured, and finally dissolved. During this process it 
happens that in some instances another delicate double contour 
is observed inside of that representing the membraneous layer 
(Fig. 33). This phenomenon may be explained by supposing the 
surface of the contracted protoplasm to have been rendered more 
dense by the action of the hydrate of chloral than the rest of the 
mass, in consequence of which it may resist longer the continued 
and subsequent solvent action of the reagent, and manifests itself 
like the membraneous layer of the blood-corpuscle in the form of a 
double contour. But it also disappears finally by the continued 
action of the reagent, and nothing but the original double contour 
representing the membraneous layer is left. 
Exposing the blood-corpuscles of the Amphiuma to the action 
of nitric acid vapour for about two minutes, the following changes 
are observed to take place. At first, while retaining their colour, 
they are rendered very distinctly granular. Gradually becoming 
paler, they are finally entirely discoloured, retaining a delicate, 
finely-granular appearance with a distinct double contour of a 
greenish tint (Fig. 3i). They retain their natural size, and most 
of them also their oval form. None of them are observed with 
folds ; and as blood-corpuscles with some folds or wrinkles are met 
with in most specimens of fresh blood, it may be supposed that this 
reagent renders them smooth again. The nucleus is coarsely 
granular, almost natural, though more distinct. 
In applying the nitric acid liquid to a specimen of fresh blood, 
the changes taking place in the structure of the blood-corpuscles 
are very striking. The granules in the interior of the nucleus 
become dissolved, causing this body to swell and appear cloudy, 
while its wall is rendered very distinct. The protoplasm appears 
in the form of a network, with larger and smaller round, oval, or 
angular meshes, which in some cases are arranged in a radiating 
form ; the largest at the inner surface of the membraneous layer, 
the smaller ones near the nucleus (Fig. 35). The double contour, 
representing the membraneous layer, remains distinct from the 
coagulated protoplasm, and in many corpuscles an interspace 
occupied as it seems by some fatty material exists between these 
two parts, or between the protoplasm and the nucleus. The form 
of the greater part of the blood-corpuscles has become irregular, 
and their size reduced. 
Nitric acid diluted with equal parts of water produces almost 
the same changes in the blood-corpuscles as when applied pure. 
The granules within the nucleus are not always found dissolved, 
nor are the interspaces betweeii the protoplasm and the membra- 
neous layer or the nucleus met with so frequently (Figs. 30 
and 37). 
Ether causes the colouring matter of the blood-corpuscles to 
