152 HISTOLOGY OF THE TEETH. 



near the edge of the cover-glass and allowed to run under, these 

 granular bodies will disappear, and at the same time large numbers 

 of bubbles accumulate, and force themselves out from under the 

 cover-glass. In this experiment, we have a positive demonstration 

 of the presence of carbonate of lime in the meshes of the stellate 

 cells of the fully-developed enamel organ previous to the beginning 

 of the process of calcification of the enamel. 



Bibliography. — Klein and Smith, Atlas of Histology : Journal 

 of Royal Microscopical Society ; Strieker, Manual of Histology ; 

 Tomes, Comparative and Human Anatomy ; Boedecker, Dental 

 Cosmos, XXI., 409 — 416; Heitzmann, Microscopical ' Anatomy 

 of Human Teeth, Med. Rec, N.Y., '76, XV., 187; Harris and 

 Power, Handbook for Physiological Laboratory; Frey, Technico- 

 logy of the Microscope ; Ranvier, Traits de Histologic ; Dr. 

 Brittain ; Dr. Jacobs, Ohio ; and various dental and medical 

 journals. 



Discovery by Observation. — The circumstances attending 

 an archaeological discovery recently made in German Altenburg, 

 on the Danube, illustrate in the most striking manner the value of 

 intelligent observation. 



Professor Hauser was interested for a month in watching the 

 colours of an extensive corn-field, which varied in every part. He 

 found an elevated post of observation, and, after a week's close 

 attention, declared it to be his opinion that the corn was growing 

 over the site of an ancient amphitheatre. His drawings showed 

 that the oblong centre piece was somewhat concave, and the 

 corn was quite ripe in that part, because there was much soil 

 between the surface and the bottom of the theatre. Elliptical 

 lines of green, growing paler the higher they rose, showed the 

 seats ; and lines forming a radius from the centre showed the walls 

 supporting the elliptical rows of seats. Excavations were made as 

 soon as the corn had been harvested, which confirmed the pro- 

 fessor's theory in nearly every particular. At six inches below the 

 soil the top of the outer wall was found, and from there the soil 

 gradually grew thicker until the bottom of the arena was reached, 

 the pavement of which is in perfect condition. From the theatre 

 a paved road leads to the Camp of Carnuntum. 



