270 
VARIETIES. 
day, and the mixture allowed to settle in a warm place, the limped straw- 
colored oil rises to the surface, leaving a copious white deposit. The watery 
solution, rendered clear by filtration, contains intact all the acetate of lead 
at first employed, and may be used in the next operation, after the addition 
to it as before, of eighteen ounces of litharge. 
By filtration through paper or cotton, the oil may be obtained as 
limpid as water, and by exposure to the light of the sun it may also be 
bleached. 
Should a drying oil be required absolutely free from lead, it may be ob- 
tained by the addition of dilute sulphuric acid to the above, when, on being 
allowed to stand, a deposit of sulphate of lead will take place, and the 
clear oil may be obtained free from all trace of lead. — London Pliarm. Journ. 
April, 1852. 
On the State in which Oxygen exists in the Blood. By Baron Liebig. — 
According to the opinions of some Chemists oxygen is not chemically com- 
bined with, but is merely absorbed by, the blood, and in proof of this 
opinion the fact is cited that the absorbed oxygen can be expelled by car- 
bonic acid. This inference is, however, according to the author, incorrect, 
and for the following reasons : — 1000 volumes of water shaken with air and 
completely saturated therewith, absorb, according to Gay Lussac, only 
volumes of oxygen and 18k volumes of nitrogen gas, while, according to the 
experiments of Magnus, 1000 volumes of blood will appropriate from 100 to 
130 volumes of oxygen, and from 17 to 33 volumes of nitrogen. If the ab- 
sorbed oxygen be contained only in one part of that fluid, that must be its 
water, which it is known under the same conditions absorbs from 11 to 14 
times less oygen ; the greater activity of its absorption by blood must be 
owing to some definite element which has a stronger affinity for oxygen than 
water possesses. 
If the attractive power which the blood exercises towards oxygen be but 
slight, it does not thence follow that it is not chemicar.y united. On the 
contrary, it is well known that the presence of one per cent, of phosphate 
of soda in water doubles its power of absorbing carbonic acid, over that of 
pure water at the ordinary atmospheric pressure. Solution of sulphate of 
iron will absorb forty times as much nitrogen as pure water can. Both of 
these solutions lose their gaseous contents in a vacuum, the former also by 
agitation with air, the latter by shaking with carbonic acid. It is hence 
obvious, and the conclusion applies to the blood, that absorption is greater 
in water holding salts in solution than in water alone. 
A fluid then may be in two conditions, on either of which its absorbent 
power over gases may be dependent, viz., under pressure which condenses 
the gas, or chemical affinity exerted by its elements upon the gas. 
If the oxygen of the blood were simply absorbed, then it must take up 
from the air, which contains only one-fifth of oxygen, twelve per cent, of 
