Ld 
TRANSACTIONS OF THE SECTIONS. 79 
Process for Preparing Hydrobromic andHydriodic Acids. 
By Dr. R. W. Grover, of Newcastle. 
Dr. Glover having observed that the solid bromide and iodide of 
barium are decomposed by sulphuric acid, with the evolution of hydro- 
bromic and hydriodic acids, without bromine or iodine being set free, 
proposed the employment of these salts of barium as very convenient 
sources of the above-named hydracids in atomic proportions. 
On a Method of separating, by Filtration, the Coagulable Lymph from 
Liquid Human Blood. By Prof. ANDREW BUCHANAN. 
Dr. Buchanan showed several specimens of coagulable lymph sepa- 
rated by filtration from human blood while yet liquid, immediately after 
issuing from the vein. He thought the process for obtaining it might 
not be without interest to those engaged in the prosecution of animal 
chemistry, as it enabled them to obtain the fibrin of the blood in a per- 
fectly pure state; and he knew no other process by which it could be 
so procured. The result obtained was also interesting, as serving to 
illustrate the constitution of the blood itself. It showed the coagulum 
to be formed not by the mere aggregation of the red particles, but that, 
according to the views of Berzelius, and many physiologists in our own 
country, the red particles were altogether passive in the act of coagu- 
lation, and were merely mechanically enveloped by the coagulable 
lymph, which existed in the liquid state in the blood as it circulates in 
the blood vessels. Dr. Buchanan’s process consisted in mingling toge- 
ther one part of liquid blood just drawn from the vein with six or 
eight parts of perfectly pure serum obtained from blood drawn the day 
before. Certain precautions are indispensable to the success of the 
experiment. If the blood be at once mixed with the whole of the serum, 
the red particles of the blood pass through the filtering paper along 
with the lymph and serum. Advantage must be taken of the superior 
specific gravity of the red particles in order to separate them. For this 
purpose, the liquid blood mixed with only a small quantity of serum is 
cautiously added to the rest of the serum placed in the funnel. The 
red particles subside, while the lymph mingles with the serum, and 
filtrates perfectly pure through the layer of red particles at the bottom, 
just as we filter any liquid through a stratum of sand. The mutual 
action of serum and liquid blood has not been sufficiently investigated. 
_ It has, indeed, been long known to physiologists, that the serum of the 
blood has no action upon the red particles, and they have employed it 
in their examination of the red particles under the microscope. They 
_ do not, however, appear to have pursued the inquiry further, to ascer- 
_ tain what becomes of the “ liquor sanguinis,” as it has been called, the 
_ transparent part of the blood as seen by the microscope, and of the 
fibrin which it holds in solution. To ascertain this, various proportions 
of serum and liquid blood were mingled together. When equal mea- 
sures of the liquids were used, or two or three parts of serum to one 
of blood, the coagulum formed was merely more voluminous and 
