88 
Proceedings of Royal Society of Edinburgh., [sess. 
(IY. and Y.) were observed, and it was found that crystals of car- 
bonate of lime had been thrown down in amount practically equiva- 
lent to all the calcium present in the sea water employed. 
Experiment YII. We obtained the liquor from a number of 
living oysters, and examined it before decomposition had begun. 
It appeared to be a mixture of lymph with unchanged sea water ; 
the specific gravity at 60° F. was 1*023, the amount of chlorine 
per litre was 17*56 grammes, indicating a considerable admixture of 
fresh or river water. 
The total lime in a litre of this liquor was 
whilst the total lime in ordinary sea water 
of the same sp, gr. only amounts to 
giving an excess of total lime, 
The alkalinity of the oyster liquor amounted to 
of carbonate of lime per litre, 
whilst the alkalinity of sea water of the same 
sp. gr. amounts to . 
0*7205 grammes, 
0*5316 
0*1889 
0*3675 
0*1094 
showing an increase of alkalinity 
equivalent to . . . .0*2581 
per litre. 
We have thus an accumulation of lime (in excess over that present 
in sea water) amounting to 0*1889 grammes per litre, the greater 
part of which is in the form of carbonate in solution, presumably 
in the amorphous or hydrated condition. 
Any doubts as to how this excess of carbonate of lime comes to be 
present is set at rest by the fact that the fresh and absolutely unde- 
composed liquor containing this excess of lime contains also (saline) 
ammoniacal salts equal to 18 parts per million, or about sixty times 
that present in any sea waters we have examined. 
Experiment YIII. A similar experiment was made with the 
liquor taken from living mussels (from the mussel beds at Granton), 
the results coinciding with those obtained in Ex. YII.* 
* Theoretically, urea plus two molecules of water give carbonate of 
ammonia. If, therefore, carbonate of ammonia be a stage in the formation of 
urea, it is not unnatural to suppose that, in shell-forming aiiimals, the shell 
formation may be the stage without any formation of urea. For special method 
for the determination of saline ammonia in sea water, see page 101, Appendix. 
