Blood-cov]puscles of A. tridactylum, &c. By Dr. Schmidt. 119 
tion is carefully examined with a first-class objective of sufficient 
amplification, it will be found that they have not run into each 
other, but that, on the contrary, the outlines of almost every 
individual may be discerned, however distorted they may he. 
As in this experiment the blood-corpuscles are pressed com- 
pletely fiat, they represent minute plates with level surfaces, 
through which the rays of light pass without undergoing much or 
any refraction, except in places where a difference in the properties 
of their substance might exist. But, as the membraneous layer is 
probably somewhat differentiated from the rest of the body, it is 
seen at the margin of the blood-corpuscle in the form of a light 
greenish border. By applying a drop of water to the preparation 
before it has become dry, the blood - corpuscles are gradually 
rendered pale and faint ; and their greenish borders will now 
appear in the form of distinct delicate double contours, as described 
before. In proportion to the amount of pressure previously sus- 
tained, they will retain their dimensions and their flatness ; and 
in those places where they were crowded before the application of 
pressure, whether mutual or by the covering glass, and in conse- 
quence much distorted in shape, they will be seen separating from 
each other as the water takes effect, and floating away, presenting 
the same appearances as the others described. 
In the course of my investigations into the structure of the 
coloured blood-corpuscles of Man, I also studied the effect of 
various reagents, such as chloroform, acetic, nitric, and carbolic 
acids, alcohol, as well as solutions of hydrate of chloral, boracic 
and chromic acids, &c., either in the gaseous or liquid form, 
upon these bodies. The changes observed to take place on these 
corpuscles by the action of these agents are, though not in every 
instance exactly alike, yet similar to those we have seen to occur 
on the blood-corpuscles of the Amphiuma or the Frog ; they 
mainly consist in the escape or destruction of the haemoglobin, 
contraction or coagulation of the protoplasm, change of form, &c. 
As I have described them before in connection with the blood- 
corpuscles of these Amphibia, they require no further remarks for 
our special purpose, except that they all appear to corroborate 
my view of the simplicity of. the structure of the non-nucleated 
coloured blood-corpuscle, as well as of that of the nucleated. 
In concluding this treatise on the structure of the coloured 
blood-corpuscles, I have only to add that I still believe a part of 
their function to be secretory. In accordance with this view I 
regard them as true glandular cells, which, independent of the 
part they may act in the transfer of ozone, are also engaged in 
appropriating certain materials from the plasma of the blood, in 
order to transform them into other bodies by virtue of their secre- 
tory power, and to finally return them to that fluid in the special 
