0 TIEDMANN’S l*iIVS10L0GV~CIIEMICAL MIXTURE OF SUBSTANCES. 
arterial. 'I’he arterial blood mixed with 
vinegar, as well as the veinous blood, left 
over mercury for 3 weeks, was converted into 
a blackish brown mass without being separat- 
ed into serum and coagulum. About the 
same period, without a knowledge of the 
Heidelberg experiments, Ed. Ch. F. Strome- 
yer obtained the same results.* 
How do these facts agree with the present 
theories of respiration '1 
Lavoisier conceived that without coming in 
contact with the respired air, a liquid consist- 
ing principally of carbon and hydrogen is 
absorbed through the pulmonary membranes 
into the bronchi, and is converted into carbo- 
nic acid and water through the oxygen of the 
inspired air. As this theory does not render 
it necessary to suppose free carbonic acid in 
the blood, it is not at variance with 'the ob- 
servations of Gmelin and I'iedemann, but the 
passage of gases into moist animal mem- 
brane, and also the immediate contact be- 
tween air and blood cannot be well doubt- 
ed of. Davy inferred from his results that 
air passes through the moist coats of the pul- 
monary vessels, and is taken upbythe s-rum, 
the oxygen partly forming with the carbon of 
the cruor carbonic acid, and partly combin- 
ing with the cruor. When he found that 
after the inspiration of hydrogen some car- 
bonic acid was expired, tliough much small- 
er in quantity than after the inspiration of air, 
he concludeil tliat veinous blood contains 
some free carbonic acid. According to the 
observations already given, it appears that 
the arteri.d and veinous blood contain no free 
acid but carbonic acid combined with alkali. 
And if we supitose acetic acid to be formed in 
respiration, (for we find it in the blood and in 
most organic liquids which are exposed to 
the influence of air in combination with 
alkalies), then must the veinous blood con- 
tain more alkaline carbonate than the arterial, 
when by the formation of acetic acid a porti* 
on of thealkaline carbonates will be convert- 
ed into acetates. 
By means of a barytes solution in an ex- 
hausted receiver, they estimated that 10,000 
parts of arterial blood contain 8.3 of combin- 
ed carbonic acid, and 10,000 parts of vein- 
ous blood 12'3 of acid in the same state, 
being in the proportion of 2 to 3. 
They sum up their views of respiration in a 
few propositions : — 
1 . That in the pulmonary cells inspired air 
is absorbed into the moist membranous ves- 
sels, and is thus brought in contact w-ith the 
blood. 
2. The azote of the air is not sensibly ab- 
sorbed by blood, but almost the whole of it 
remains in the cells. On the contrary, as 
oxygen is taken up by the blood abundantly, 
it flows out of the cells into the vessels in 
proportion to its absorption, and the mixture 
of gas remaining in the lungs must therefore 
contain more azote and less oxygen than the 
air. 
3. The oxygen taken up by the blood com- 
bines partly with carbon and hydrogen, and 
* Schweigg'. Journ. four Cliem. Ixiv. 105, 
t Memories de I’acad des Sc, An, 1790, insert- 
ed in Scherer’ Journal der Chemie x, 5G0, 
forms carbonic acid and water, and partly 
unites with the solid organic compounds con- 
tained in the blood. From these proceed 
acetic or lactic acid, which combines with a 
portion of carbonate of soda contained in the 
blood, and drives its carbonic acid into the 
cells. 
4. The acetate of soda loses in its course 
through the different secreting organs its 
acetic acid, combines again with carbonic 
acid after undergoing many decompositions 
in its passage with the mass of blood through 
the body, and enters into the lungs on its 
return as carbonate of soda. 
TIEDEMANN’S PHYSIOLOGY, 
TRANSLATED BY GULLY AND 
LANE. 
PARALLEL BETWEEN THE MATERIAL COMPO- 
SITION OF ORGANIC BODIES AND THAT OF 
INORGANIC BODIES. 
On the Chemical Mixture of Substances, 
V. All organic and almost all inorganic 
bodies are composed of simple materials, di- 
versely combined witheacli other, and which 
may be separated by chemical operations. 
However, when we compare the composition 
of these two groups of bodies, we recognise 
important difterences between them. 'Jhus 
the first are for the most part assemblages of 
particular combinations, which we first meet 
with when we chemically analyse plants and 
animals. There are, in the vegetable king- 
dom, starch, vegetable albumen, gluten, gum, 
sugar, &c. ; in the animal kingdom, animal 
albumen, fibrin, gelatin, mucus, &c. These 
matters are called by chemists the immediate 
or proper matters of organized bodies, or the 
simple organic compounds,* 
VI, in submitting anew the immediate 
principles of organic bodies to chemical an- 
alysis we obtain the mediate principles, or 
the simple matters, which chemistry has not 
yet further decomposed, and which for this 
reason are denominated elements. The pon- 
derable mediate principles of organic bodies 
are : 
A, Non-metallic substances ; namely, 1 
oxygen, 2 hydrogen, 3 carbon, 4 nitrogen, 5 
phosphoius, 6 sulphur, 7 iodine, 8 bromine, 
9 chlorine, and 10 fluorine. 
B. Metallic substances : 
a. Alkaline metals — 11 potassium, 12 so- 
dium, and 13 calcuim. 
b. Earthy metals— 14 magnesium, 15 si- 
licium, and 16 aluminum. 
c. Ponderous metals— 17 iron, 18 man- 
ganese, and 19 copper. 
Among impondeiable substances those 
which can in some circumstances be recognis- 
ed in organic bodies, are light, heat, and 
electricity. 
* The French chemists call them “ les prin- 
cipes iminediats organiques” We may give 
them the name of organic matter or those adapt- 
ed to life, because they are essential constituent 
parts of living beings and the phenomena of life 
are perceived only in bodies that are composed 
of such. 
