14 



LIVING PROTOPLASM AND 



One of the most interesting labil atomic groups is the 

 aldehydegroup — C^h > ' 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 : 



„=0 n -0-H „=0 ^-O-H 



— L_ H — ^ — ^-H — L - 



(i) (2) (3) (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, -CH 



One of the laws of lability can therefore be generally ex- 

 pressed thus : // 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/zncfo-benzaldehydes show a far greater lability 

 as nitro-ov o.vy-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 



