450 The American Naturalist. [May, 
portion, however, of phosphoric acid had, on the contrary, 
been reduced from 38.93 to 35.06. There had been a forma- 
‘tion of fluoride of calcium at the expense of the original 
phosphate of lime and carbonate of lime, and a mixture which 
contained more fluorine than apatite had been formed ; for 
the latter would have contained only 3.13 of fluorine instead 
of 4.74. 
Experiments 2 and 3—Two analogous experiments were 
made with solutions of chloride in which were placed the 
fragments of the bones of the manatee containing at the be- 
ginning 1%% of one per cent of chlorine in the form of an insol- 
ublecompound. After remaining for three months in a solution 
of one tenth of chloride of sodium, we showed roo of one per 
cent (0.16) of insoluble chlorine. After three months in solution 
of one-twentieth of chloride of sodium and one-twentieth of 
chloride of calcium, the bones contained 0.24 per cent of 
chlorine in an insoluble state. Therefore, there had not 
been any fixation of chlorine by the action of chloride of 
sodium alone on the phosphate of lime, but it was by the 
action of chloride of calcium; the proportion of chlorophos- 
phate formed was otherwise much less than that of fluophos- 
phate produced by a solution, even very feeble, of an alkaline- 
fluoride. We can conclude that the affinity of phosphate of 
lime is much greater for the fluoride than for the chloride. 
Experiment No. 4.—In other experiments, instead of using an 
alkaline-fluoride easily soluble in water, there was employed 
fluorspar in fine powder, to which was added distilled water, 
with a little carbonate of ammonia, a salt which frequently 
forms near, on, or in the bone by reason of the decomposition 
of organic matter, and which can aid in the solution of a 
small quantity of fluoride of calcium. 
The fragments of the bones of the manatee were placed in 
an uncovered vessel with sand, with 200 cubic centimetres of 
distilled water and 2 grams of carbonate of ammonia, and it 
was noticed that the proportion of fluorine which, at the be- 
ginning, was 0.31 per cent, became 0.35 at the end of the 
month and 0.43 at the end of three months. While the bones 
were thus immersed, the solution was frequently shaken and 
