THE BEGINNINGS OF LIFE. 



^Z 



into a single larger calculus. The change is a most 

 remarkable one, during which there is brought about 

 ^ the perfect coalescence into one, of two or more glo- 

 bules of carbonate of lime as much as xiV of ^.n inch 

 in diameter, perfectly transparent, of a hardness nearly- 

 equal to that of glass . . . the incorporation of these 

 globules being so complete, that the resulting one has 

 the same spherical form, the same degree of trans- 



FiG, 41. 



Globular Carbonatg of Lime in later stages — formation of Calculi by 

 ' Molecular Coalescence.' (Rainey.) 



a a' a" Mulberry-like bodies due to the aggregation of several small 

 globules. These gradually undergo change from circumfer- 

 ence to centre. The external globules first coalesce into an 

 amorphous granular layer, which gradually becomes more 

 transparent, and similar changes extend inwards. 

 h h' h" h'" Further stages of aggregation and molecular coalescence. 



