298 JAMES CRAWFORD WATT. 



centration of the reacting salts and in the diffusion currents in 

 different parts of the solution. Side by side may be found an area 

 of crystals and of perfect spherules, or both forms may be seen 

 mixed in one area. 



In passing from the sodium carbonate end of a cell across the 

 precipitate to the calcium chloride end there is often seen a marked 

 change in shape of the deposit, forms present to one side of the 

 line of contact of the two solutions not being present on the other. 

 Spherules may occur all to the one side, but follow no rule as to 

 which they select. Transition forms occur from one area to an- 

 other. Orde found similar conditions on sectioning plugs of coag- 

 ulated albumen with which he had sealed the ends of capillary tubes 

 containing solutions which gave precipitates in the plugs when the 

 sealed ends of the tubes were immersed in certain other solutions. 



The multitude of forms exhibited in the precipitate of calcium 

 carbonate in the slides seemed remarkable, but on referring to 

 Goldschmidt's "Atlas der Krystallformen," I found illustrations 

 for 2,544 modifications of the crystal form of calcite which have 

 already been observed. Many of the changes are slight, but all 

 are quite evidently different, and among them may be recognized 

 all the types of crystal form I have obtained. Spherules and their 

 variations were not shown. 



PART 2. EXAMINATION OF BONE. 

 Technique and Material. 



The ordinary method of examining bone by means of very thin 

 ground sections, or by sections cut from decalcified bone, are use- 

 less to give the structure of the matrix. A method just published 

 by Bast, however, for the study of bone cells in situ, without cut- 

 ting sections, is equally applicable for the examination of the matrix 

 and was here employed. 



Bast worked with the parietal and ethmoid bones of mice and 

 young rats, rabbits, cats and dogs, the nasal conchse of these ani- 

 mals, pieces of the ethmoid in man, and other bones thin enough 

 to be transparent. These were mounted whole. The specimens 

 were fixed in 95 per cent, alcohol, washed in water, stained for 





