OF LIVING MATTER 71 



is a constant change, as rotation in nature, from crystalloids to 

 colloids, and from colloids to crystalloids." 



These facts sufficiently show that, notwithstanding all their differ- 

 ences in property, the transition is fairly easy from the one to the 

 other isomeric state. And if simple saline substances can pass into 

 the colloidal condition, it surely should not be difficult to imagine 

 that molecular rearrangements may take place among the con- 

 stituents of ammoniacal salts of greater complexity, whereby a 

 colloid may be produced capable of entering into the formation of 

 that simplest form of protoplasm, such as must be engendered by 

 the Bacteria that grow and multiply, as I have shown, in a simple 

 solution of tartrate of ammonia in distilled water. The simplicity 

 of their life-processes must exceed that of the nitrifying Bacteria, 

 just as this in its turn exceeds that of the simplest Algae (the 

 Chromacea) : though in each case their protoplasm is directly 

 fashioned by the synthesis of inorganic elements. 



If the living unit — the unit of protoplasm — is itself constituted, as 

 is commonly supposed, by a grouping of colloid molecules, we are 

 introduced to a substance whose molecular diversity may well be 

 as endless as that of the countless simple forms of life, together with 

 the similar variety of tissue elements of which plants and animals 

 are constituted. In its simplest form protoplasm exists as a jelly- 

 like, slightly granular, semi-fluid substance, without visible structure, 

 though it is presumed to have an excessively minute sponge-like or 

 foam-like character ; and to be capable of absorbing dissolved 

 matter from without, as a preliminary process leading on to assim- 

 ilation and growth. But as Haeckel says,' "We have as yet no 

 knowledge of the fundamental features of its very variable chemical 

 structure. The one thing that bio-chemists have told us about it is 

 that the molecule of plasm is very large, and made up of a great 

 number of atoms (over a thousand) ; and that these are combined 

 in smaller or larger groups, and are in a state of very unstable 

 equilibrium, so that the life process itself causes constant changes 

 in them." 



This then is the material that was spoken of by Huxley as ' The 

 Physical Basis of Life ' ; and the upholders of the Protoplasm or 

 Sarcode theory maintain that this substance has an essential unity 

 of nature. So that, in spite of multitudes of minute specific and 

 isomeric differences, we have in reality to do with one and the 



' " The Wonders of Life," 1904, Transln. p. 140. 



