76 Transactions of the Royal Microseoincal Society. 
irregular mass upon the nucleus, which becomes hidden from view. 
The rest of the body, after having considerably contracted and 
assumed an irregular angular form, breaks up into small fragments. 
After an exposure of about ten minutes, the blood-corpuscles become 
entirely discoloured, the nucleus before hidden reappears, showing 
a distinct irregular serpentine double contour, and also the granules 
in its interior. 
The changes taking place in these blood-corpuscles when 
treated with the solution of the hydrate of chloral are very interest- 
ing and important, as they manifestly show the existence of the 
membraneous layer of these bodies, such as I have described it. 
Thus, after the solution has been applied, the protoplasm of the 
blood-corpuscle without much or any alteration of form gradually 
contracts upon the nucleus. As the result of this contraction, it 
hecornes entirely separated from the membraneous layer, which 
inanifests itself in the form of a delicate double contour (Figs. 30, 
31, and 3l^). The interspace left between the contracted proto- 
plasm and the double contour representing the membraneous layer 
is very considerable, as will be seen from the drawings, and it 
seems to me should be sufficient evidence to prove the existence of 
such a layer to an unbiassed mind. 
At first the protoplasm is observed to become coarsely granular. 
When its contraction and simultaneous separation from the mem- 
braneous layer commences, it assumes a fibrillar appearance at its 
periphery (Fig. 32), and as the metamorphosis proceeds similar 
fibrillar rings concentrically arranged appear throughout the whole 
mass (Fig. 30). A number of coarse granules are observed to 
adhere to the contracted mass or to its periphery. In fact, it 
appears almost as if those concentrically arranged fibrillm were 
produced by a fusion of granules. The contracted protoplasm 
retains its yellow colour, while the membraneous layer and also the 
vacuum left between it and the former are perfectly clear. Although 
the general oval form of the blood-corpuscle, especially of its mem- 
braneous layer, remains unaltered during the whole process of 
metamorphosis, its size is very considerably reduced ; for in many 
instances its long diameter amounts only to yf ffo in length, 
or seven less. Considering this great diminution in the size of the 
blood-corpuscle, it seems that when the protoplasm commences to 
contract the membraneous layer contracts simultaneously to a 
certain limit, beyond which it cannot contract any farther ; if then 
the contraction of the protoplasm continues, a separation from the 
membraneous layer must be the result. The nucleus undergoes 
almost no change by the action of this solution ; it is only rendered 
more distinct. 
When the action of the solution of the hydrate of chloral is 
allowed to continue for some time, the contracted protoplasm is 
