l68 LIFE AND DEATH. 



The consideration of the properties of turgescence 

 and of swelling, which very generally belong to 

 organized tissues, and therefore to the organic 

 substance of protoplasm, has enabled us to obtain 

 some idea of its ultra-microscopic constitution. If 

 we wet a piece of sugar or a morsel of salt, before 

 they are dissolved they absorb and imbibe the water 

 without sensibly increasing their volume. It is quite 

 otherwise with a tissue {i.e., with a protoplasm) 

 when weakened in water as a preliminary. The 

 tissue, plunged into the liquid, absorbs it, swells, and 

 often grows considerably. And this water does not 

 lodge in the gaps, in pre-existing lacunar spaces, for 

 organic matter presents no gaps of this kind. It 

 does not resemble a porous mass with capillary 

 canals, such as sandston'e, tempered mortar, clay, or 

 refined sugar. The molecules of water interpose 

 between and separate the organic molecules, thus 

 increasing by a sort of intussusception the intervals 

 separating the one from the other — molecular intervals 

 escaping the senses, as do the molecules themselves 

 because they are of .the same order of magnitude. 



Micellar Theory. — While pondering over this 

 phenomenon, an eminent physiologist, Nageli, was 

 led in 1877 to propose his micellar theory. Micellae 

 are groups of molecules in the sense in which 

 physicists and chemists use the word. They are 

 molecular structures with a configuration. They 

 rapidly absorb water and are capable of fixing a 

 more or less thick and adherent layer of it to their 

 surface. In a word, they are aggregates of organic 

 matter and water. 



There is therefore every reason for believing that 

 the microsomes of spongy protoplasm, the physical 



