?/^ 



^^^£. 



s a 



THE BEGINNINGS OF LIFE. 



"^'^^Pound 



t 



53 



'^^nium (]\TT,' of the molecules of which they are compounded. Prof. 

 ^c elements; ' Graham says : 



;eth 



cr to 



elcm 



cnt 



did 



constj 

 mai; 



<■ It is difficult to avoid associating the 



high equivalents. 



high number appears 



to be 



e 



such 



"^7 N3 0,), or 

 3dics know 



as 



^■ 



zed at the 



mar 



inertness of colloids with their 



particularly where the 

 attained by the repetition of a smaller number. The 

 enquiry suggests itself whether the colloid molecule 

 may not be constituted by the grouping together of a 

 number of smaller crystalloid molecules, and whether 

 the basis of colloidality may not really be this com- 



be attained r posite character of the molecule.' In all probability, 



llts. two of the distinguishing characteristics of colloids, 



ith atomic li namely, their very slow rate of diffusion and their 



this light, tk; want of any tendency to assume a crystalline form, 



simple and i are referrible to this large size and complexity of the 



alike have i molecules of which they are compounded. No hard 



ccules maybe: and fast line, however, separates the colloids from the 



multitudes of bodies exist 



L 



, or unlike # crystalloids. 



Although 



T 



crystallizable 



comp 



ounds 



which may be easily placed in one or the other class, 

 multitudes of others are to be met with having 

 properties of an altogether intermediate character. 



te what 

 kable 



i^gjif Nay, even the most typical colloids may undergo a 



mar 



c 



rearrangement 



of their elements, whereby they are 



are 



suppose' 



converted into crystalloids^. 



Nothing 



could show 



re size a 



nd co^l 



5 are 



the 



more plainly than this that the difference between a 

 crystalloid and a colloid is merely one of degree, and 

 j^-ttof that the properties of colloids are different merely by 



said to 5 

 + 2 ' 



reason of the more complex molecular arrangement 



15 



HO 



^ See p. 39. 



\ 



1 I 



