1 84 / LIONEL TAYLER [September 



different results. These two forms have developed on their separate 

 lines and have resulted in the most important divisions of organic 

 life, the animal and vegetable kingdoms ; and the most marked 

 difference between these two kinds of protoplasm appears to lie in 

 the fact that one has to exist on comparatively complex foods, the 

 other on comparatively simple. Excluding this and other differences, 

 for the moment, from consideration, there remain three peculiarities 

 which distinguish protoplasm from inorganic material: — (1) It is 

 extremely complex in structure ; (2) it is remarkably unstable ; and 

 (3) it has the power, when placed under suitable conditions, of build- 

 ing up from its environment material similar to or identical with its 

 own. 



Lewes, Spencer, and, in a crude unscientific form, many early 

 writers, have noticed certain resemblances between some kinds of dead 

 and living material ; these resemblances have steadily multiplied in 

 number, while they have become far more forcible in character during 

 the last forty to fifty years, so that many, perhaps most, scientists are 

 beginning to assume, consciously or unconsciously, that purely physical 

 and chemical causes are or soon will be sufficient to explain the lower 

 and possibly also the higher forms of life. 1 Let us take first the pecu- 

 liarities of protoplasm which are apparently most allied to chemical and 

 physical phenomena, its extreme instability and complexity. Making 

 a general statement of the characteristics of the chemical elements, it 

 appears that they may be grouped into three more or less ill-defined 

 divisions — those with marked affinities, others with very ill-marked 

 tendencies, and a third intermediary division. Stability is usually 

 associated in chemistry with simple molecular structure ; satisfied 

 affinities and compounds are generally stable when they are made up 

 of elements which exhibit strong mutual affinities, combined in such a 

 way that each tendency is more or less completely balanced by others. 

 The more perfectly the elements are brought into contact, the more 

 combination of these elements is accelerated, and, finally, there is an 

 evolution of energy whenever the less stable passes into the more 

 stable. 



Chemical instability, on the other hand, is associated with weak 

 affinities, great complexity, and a combination of elements in a form 

 which by readjustment might lead to the formation of simpler 

 and more stable compounds. As there is always an evolution of 

 energy when the less stable passes into the more stable, there is 

 manifestly a storage of potential energy in the unstable forms. The 

 instability and complexity of protoplasm is therefore really not a 

 difference from, but a resemblance to, non-living substances, because 

 its instability and complexity apparently exist under similar, though 

 accentuated, conditions to those cases where the complexity and in- 

 stability is purely chemical. The distinctive characteristic of living 



1 Verworn in his "General Physiology" gives a fairly complete summary of tins position. 



