THE ACTIONS OF FORCES ON ORGANIC MATTER. 41 



in the bodies of animals, those parts which carry on active 

 functions are nitrogenous; while parts that are non-nitro- 

 genous — as the deposits of fat — carry on no active functions. 

 And we even find that the appearance of non-nitrogenous 

 matter throughout tissues normally composed almost wholly 

 of nitrogenous matter, is accompanied by loss of activity: 

 what is called fatty degeneration being the concomitant of 

 failing vitality. One more fact, which serves to make 



still clearer the meaning of the foregoing ones, remains — the 

 fact, namely, that in no part of any organism where vital 

 changes are going on, is nitrogenous matter wholly absent. 

 It is common to speak of plants — or at least all parts of 

 plants but the seeds — as non-nitrogenous. But they are only 

 relatively so; not absolutely. The quantity of albumenoid 

 substance in the tissues of plants, is extremely small com- 

 pared with the quantity contained in the tissues of animals; 

 but all plant-tissues which are discharging active functions 

 have some albumenoid substance. In every living vegetal 

 cell there is a certain part that includes nitrogen as a com- 

 ponent. This part initiates those changes which constitute 

 the development of the cell. And if it cannot be said that it 

 is the worker of all subsequent changes undergone by the 

 cell, it nevertheless continues to be the part in which the 

 independent activity is most marked. 



Looking at the evidence thus brought together, do we not 

 get an insight into the actions of nitrogenous matter as a 

 worker of organic changes? AVe see that nitrogenous com- 

 pounds in general are extremely prone to decompose: their 

 decomposition often involving a sudden and great evolution 

 of energy. We see that the substances classed as ferments, 

 which, during their own molecular changes, set up molecular 

 changes in the accompanying carbo-hydrates, are all nitro- 

 genous. We see that among classes of organisms, and among 

 the parts of each organism, there is a relation between the 

 amount of nitrogenous matter present and the amount of 

 independent activity. And we see that even in organisms 



