On the Composition of the Blood. 
217 
directly to nutrition, by the setting at liberty of their contents, 
which are then found to have a tendency to fibrilisation ; whih? 
others have thought that they were the elaborators of the albumen 
into fibrine. Others, again, consider that they originate the red 
cells by a higher degree of development, and this probably is 
their chief use. 
The circulation of the white cells through the vessels is slower 
than that of the red ; and as they are often found close to the sides 
of the interior of the capillaries, as if adhering thereto, and out 
of the principal force of the passing current, this circumstance has 
given support to the view of their ministering immediately to 
nutrition. The opinion receives some further confirmation from 
the fact that wherever active development is going on, there is 
always found a relatively greater number of these cells. 
The blood of plethoric animals is rich in white cells : besides 
which these bodies seem to have a remarkable tendency both to 
increase in number and to accumulate in the vessels when 
diseases of an inflammatory nature supervene on such a state of 
system. In that abnormal state of the blood also, which is. 
ordinarily termed buffy blood, and which belongs especially to 
many inflammatory affections, the white cells help in a great 
degree to make up the so-called sizy or buffy crust of the blood. 
We thus see that variation in their number and also in their 
comportment within the vessels takes place when disease exists, 
showing that they, in common with every other constituent ol 
the blood, undergo important changes under such untoward 
circumstances. 
We must not, however, anticipate that which has to be 
stated with reference to blood-diseases ; and, therefore, having 
now described the chief constituents of the circulating fluid, and 
shown the several important offices which each fulfils in the 
promotion of health and development, we purpose to conclude 
the present paper, intending in our next to speak of the circu- 
lation of the blood and the phenomena connected therewith, with 
an especial view of explaining the pulse and the changes it 
undergoes both in frequency and character, depending on 
certain morbid states of the system. Besides this, it is our in- 
tention to direct attention to some of the maladies which have 
their origin in a changed condition of the blood itself. 
[To be continued.] 
