THE DEVELOPMENT OF THE TEETH. 149 



resultant lime salt will go down as an amorphous powder, 

 or, under some circumstances, in minute crystals. But in 

 the presence of gelatine, albumen, and many other organic 

 compounds, the form and physical character of the lime 

 salts are materially altered, and in the place of an amor- 

 phous powder there are found various curious but definite 

 forms, quite unlike the character of crystals produced with- 

 out the intervention of the organic substance. 



Mr. Rainie found that if calcium carbonate be slowly 

 formed in a thick solution of mucilage or albumen the re- 

 sultant salt is in the form of globules, laminated in structure, 

 so that the globules may be likened to tiny onions ; these 

 globules, when in contact, becoming agglomerated into a 

 single laminated mass, it appearing as if the laminse in 

 immediate apposition blended with one another. Globular 

 masses, at one time of mulberry-like form, lose the in- 

 dividuality of their constituent smaller globules, and become 

 smoothed down into a single mass ; and Mr. Rainie suggests 

 as an explanation of the laminated structure that the smaller 

 masses have accumulated in concentric layers which have 

 subsequently coalesced ; and in the substitution of the 

 globular for the amorphous or crystalline form in the salt of 

 lime when in contact with various organic substances, 

 Mr. Rainie claimed to find the clue for the explanation of 

 the development of shells, teeth, and bone. At this point 

 Professor Harting took up the investigation, and found that 

 other salts of lime would behave in a similar manner, and 

 that by modifying the condition of the experiment very 

 various forms ( l ) might be produced. But the most im- 

 portant addition to our knowledge made by Professor 

 Harting lay in the very peculiar constitution of the " calco- 

 spherites," by which name he designated the globular forms 

 seen and described by Rainie. That these are built up of 



(*) Thus he was successful in artificially producing "dumb-bell'* 

 crystals. 



