FACTS AND OBSERVATIONS. 
711 
Experiments on the Respiration of Plants,, &c. 
—At a late meeting of the Munich Academy of Sciences, 
Baron Liebig presented an interesting paper on certain 
experiments he had made with an apparatus constructed at 
the expense of the King of Bavaria for estimating oxygen in 
various bodies. These experiments prove that not only is 
oxygen disengaged from the atmosphere by plants, but also, 
and in considerable quantities, by the decomposition of water 
in the bodies of carnivorous animals. Baron Liebig is of 
opinion that this fact will throw new light on the phenomena, 
at present so little understood, of nutrition and digestion. 
Periods when Carbonic Acid is Liberated from 
Plants. —There are two periods during the life of a plant 
when the liberation of carbonic acid gas goes on with great 
energy. One is during the germination of the seed; and here we 
can distinctly trace the object which is gained by the abstrac¬ 
tion of the oxygen from the surrounding air, and by the con¬ 
version of it into this gas, so opposite in its properties. The 
conditions requisite for the germination of the seed are 
warmth, moisture, and the presence of oxygen. The process 
is also favoured by darkness. The influence of each of these 
will be readily understood. No vital action can go on with¬ 
out a certain amount of heat, and where this is not produced 
within, it must be derived from without. The germination 
of the seed is as much dependent upon warmth, therefore, as 
the hatching of the egg of a bird, though the amount it 
requires is not nearly so great. Moisture is also evidently 
required for the conversion into a fluid state of the dry nutri¬ 
ment which has been previously stored up in the seed, and 
no change can commence until this is supplied. The presence 
of oxygen is necessary, because the conversion of starch into 
sugar requires that some of the carbon of the former should 
be set free, and this can only be accomplished by the union 
of it with oxygen, so as to form carbonic acid. This process 
is favoured by darkness, because light has a tendency to 
produce the contrary change—the fixation of the carbon 
within the structure. 
New Albumenoid Substance in Milk. —At a late 
meeting of the Academy of Sciences of Paris, MM. E. Millon 
and Commaille gave an account of (i A New Albumenoid 
Substance in Milk.” They separated casein from cow's milk 
by means of acetic acid, filtered the liquor, then heated it, 
and obtained a new’ coagulum which they found to possess 
the external characters of albumen, and also to contain the 
