ITS CHEMICO- PHYSICAL AND MORPHOLOGICAL PROPERTIES 61 



The water of adhesion consists of molecules of water, which are 

 held closely to the surface of the micella by molecular attraction. 

 '"The concentric layers of water, which compose the spherical 

 envelope surrounding the micella, vary considerably as to their 

 density and their immobility ; they are naturally most dense and 

 firmly attached when they are in direct contact with the surface 

 of the micella" (Pfeffer). 



The capillary water finally is outside the sphere of attraction 



of the individual micella? and fills up the gaps in the micellar net- 

 work. 



" These three kinds of water show considerable variation as 

 to the degree of motility shown by their molecules. The mole- 

 cules of capillary wnter are as free in their movements, as those 

 of free water ; in the water of adhesion the progressive move- 

 ments of the molecules are more or less diminished, whilst the 

 molecules of the water of constitution are fixed and non-motile." 

 Hence only the waters of capillarity and of adhesion can pass 

 through a membrane by osmosis. 



Just as water particles may be firmly held upon the surface of 

 the micella? by molecular attraction, other substances (calcium 

 and silicon salts, colouring matter, nitrogenous compounds, etc.), 

 having been taken up in solution into the organised body, may 

 be deposited upon them. The .growth of organised matter by 

 intussusception is explained by Nageli, by the supposition that 

 particles of material in solution make their way into the organised 

 body, such as, for example, molecules of sugar into a cellulose 

 membrane, where they may either become deposited upon the 

 micella? which are already present, thus adding to their size, or 

 to a certain extent they may crystallise out to form new micella? 

 situated between the ones already present. As an example of 

 this, the phenomenon of sugar molecules becoming converted into 

 cellulose molecules may be quoted. 



This micellar hypothesis of Niigeli is frequently referred to in 

 later chapters, as it often is of great use in forming a mental 

 picture of the complex arrangement of matter in the elementary 



organism. 



Literature II. 



1. Ai/nuNx. Dis FAementarorganismen u. Hire Beziehungen zu den Zellen. 



Leipzig. 1890. 



2. Jul. Arnold. Ueber feinere Structur der Zellen vnter normalen und 



pathulogischen Bedingungen. Virchows Archiv. Bd. 77, 1879, p. 181. 



