OF THE INVERTEBRATE ANIMALS. 31 



Unio. Anodonta. 



Phosphate of lime 14'85 14-91 



Carbonate of Hme, phosphate of soda, 



chloride of sodium and sulphate of lime 2*71 3*45 



In all . . 17-56 18-36 



per cent, of incombustible residue. 



We thus see that the amount of phosphate of Ume is constantly 

 so enormous, that it cannot be considered as accidental. 



On the other hand, the amorphous mucus which is found be- 

 tween the shell and the mantle, and which is mixed with but few 

 epithehal cells, when incinerated left the greater part as a colour- 

 less ash, (the characteristic odour of burning albuminates being 

 evolved at the same time,) which was soluble in acids with con- 

 siderable effervescence, and consisted almost entirely of carbonate 

 of lime. The smallest quantity only of this pre-existed in the 

 mucus, inasmuch as acids caused but slight evolution of gas in 

 the latter, whilst oxalic acid instantly produced a dense white 

 precipitate, consisting of oxalate of lime and albumen. Hence 

 the lime was contained in it, in the form of a readily decomposed 

 compound with albumen, as a soluble, perhaps basic, albuminate 

 of lime. 



If we add these two secretions together, we ought again to 

 obtain their sum, and thus the confirmation of our view, in the 

 blood of these animals. 



7-560 of the blood from the heart and auricles of about forty 

 Anodontce (obtained by puncture just before the systole), when 

 stirred with a glass rod, formed a small colourless clot, which, 

 when dried, weighed 0-0025. After the removal of these, the 

 whole was dried in a water-bath finally at 248° F. and weighed 

 0-061 . On incineration, this left 0-0302 of white ash, 0-0025 of 

 which was soluble in water : the residue, which dissolved in acetic 

 acid with considerable effervescence, yielded 0-0026 of phosphate 

 of lime. 



I must remark, that the blood when freshly drawn from the 

 heart was perfectly clear and colourless, but did not effervesce 

 with acids, consequently contained no carbonates, although it 

 had a slightly alkahne reaction : the part soluble in water con- 

 tained sulphate of lime, phosphate of soda and chloride of sodium. 

 In another portion, which I accidentally set aside over night 

 between watch-glasses, I found the next morning the whole sur- 

 face covered with a thin crystalline film. The crystals under 



