i 4 
LIVING PROTOPLASM AND 
One of the most interesting labil atomic groups is the 
aldehydegroup —* n which the oxygen exerts an attract¬ 
ing influence upon the hydrogen connected with the carbonatom, 
which is generally tetravalent, but can in some instances also 
functionate bivalent. Thus the hydrogenatom is subjected to 
continuous vibrations from the carbon to the oxygen and back, 
as may be indicated by the following formulas: 
c-°- H 
( 2 ) 
r =° 
—H 
( 3 ) 
c-°" H 
( 4 ) 
These motions are accelerated by rise of temperature ; in the 
same measure the inclinations to chemical reactions increase. 
Ammonia, diamid, hydroxylamin, hydrocyanic acid, sulfuretted 
hydrogen, primary sulfites act with great facility upon alde¬ 
hydes and even the molecular oxygen is taken up easily by 
certain aldehydes. Certain substances bring on a rapid change : 
thus a little sulfuric acid will transform ethylaldehyde into 
paraldehyde, a polymeric modification, whereby a contraction 
and development of heat takes place. Caustic potash converts 
that aldehyde into a resin. 
Another group of a certain lability is represented by the 
following position : 
—C =0 —C—OH 
I easily passing into : || 
— CH 2 -CH 
One of the laws of lability can therefore be generally ex¬ 
pressed thus: If in a chain of carbonatoms one of these atoms has 
two affinities saturated by one oxygenatom , while the other two 
affinities of the same carbonatom are saturated by positive atoms or 
groups of atoms, a labil group is formed. This lability is increased 
with the entrance of stronger positive groups and is lessened by 
negative groups; a/zwWo-benzaldehydes show a far greater lability 
as nitro-ov ozy-benzaldehydes. 
The saturated hydrocarbons, alcohols and acids of the 
methanseries are in comparison with the aldehydes very stable 
compounds; also the saturated hydrocarbons of the benzol 
series. The stability however decreases with the number of 
entering hydroxylgroups. 
Now taking the proteids into consideration, it must be borne 
