RAINEY, ON CARBONATE OF LIME GLOBULES. 27 



forms of carbonate of lime are produced in organized bodies^ 

 to which the same decisive mode of testing this fact could 

 not be so easily applied ; and in physiological science posi- 

 tive^ experimental evidence is especially needed. In merely 

 describing the different characters of the calcareous globules 

 in the glass cells before alluded to, this subject has been 

 anticipated, and therefore it only remains to show, by the 

 measurement of these globules duiing their growth, how 

 their increase of diameter and their coalescence takes place. 

 Two globules attached to the floor of a cell containing the 

 two solutions of gum, in which decomposition and the 

 formation of carbonate of lime were slowly going on, were 

 measured by means of the micrometer eye-piece on the 27tli 

 of August, 1860, and their distance apart accurately deter- 

 mined, which was 23*0 o of an inch, that is, four spaces between 

 the lines of the micrometer, each space being -25^00 of an 

 inch. On the 29th instant, the interval had become dimin- 

 ished -2:^Vo of an inch, and the diameter of the globules 

 increased accordingly. On September 10th, it had dimin- 

 ished another qzq-^ of an inch, with a proportionate increase 

 of the globules ; -s^no of an inch were now left, which were 

 gradually filled up between the present time and the 27th of 

 November, when the globules had acquired such an increase 

 of size as to be in contact. Similar measurements were made 

 of other globules, with a like result, and the experiment is so 

 easily performed that any one can, without either much trou- 

 ble or sacrifice of time, verify its correctness. As the inter- 

 val between two or more globules is in progress of being filled 

 up, none of the particles of the carbonate of lime which are 

 being added to their surface are visible, and the surface itself 

 appears perfectly smooth and sharply defined. These obser- 

 vations are best made on the globules which form on the 

 cover of the cell, these being more clear than those on the 

 floor, and if the cover be sufficiently thin, a lens of ^ or -jL. of 

 an inch focus can be employed in the examination. The 

 invisibility of the increments which these globules receive 

 during the time ordinarily employed in the examination of 

 any minute part of an object, supposing that time to be one 

 minute, will admit of an obvious explanation, on considering 

 the entire space between two globules, divided by the number 

 of minutes contained in the time required to flll it up, and 

 the extreme minuteness of each of these divisions. In the 

 above experiment, a space equal to -j^Va of an inch was filled 

 up in seventy-eight days ; hence the size of the particle added 

 to each globule in one minute would be more than the two- 

 hundred million eth of an inch in diameter. This would be 



