TISSUES OF THE CONNECTIVE SUBSTANCE. 239 x 



example of the constitution of bone-earth we give here the analyses 

 of ZALEWSKY. The figures represent parts per thousand. 



Man. Ox. Tortoise. Guinea-pig. 



Calcium phosphate, Ca 8 P,O 8 838.9 860.9 859.8 873.8 



Magnesium phosphate, Mg 3 P a O 8 10.4 10.2 18.6 10.5 



Calcium combined with CO a , Fl, and Cl. 76.5 73.6 63.2 70.3 



Co, 57.3 62.0 52.7 



Chlorine 1.8 2.0 1.8 



Fluorine 2.8 8.0 2.0 



Some of the CO, is always lost on calcining, so that the bone-ash does not 

 contain the entire CO, of the bony substance. 



The quantity of organic substance in the bones, calculated from 

 the loss of weight in burning, varies somewhat between 300 and 

 520 p. m. This variation may in part be explained by the difficulty 

 in obtaining the bony substance entirely free from water, and partly 

 by the very variable amount of blood-vessels, nerves, marrow, and 

 the like in different bones. The unequal amounts of organic sub- 

 stance found in the compact and in the spongy parts of the same 

 bone, as well as in bones at different periods of development in the 

 same animal, depend probably upon the varying quantities of 

 these above-mentioned formations. Dentin, which is comparatively 

 pure bony structure, contains only 260 to 280 p. m. organic sub- 

 stance, and HOPPE-SEYLER therefore thinks it probable that en- 

 tirely pure bony substance has a constant com posit ion and contains 

 only about 250 p. m. organic substance. The question whether 

 these substances are chemically combined with the bone-earths or 

 only intimately mixed has not been decided. 



The nutritive fluids which circulate through the bones have not been iso- 

 lated, and we only know that they contain some albumin and some NaCl and 

 alkali sulphate. The yellow marrow contains chiefly fat. which consists of 

 olein, palmitin, and stearin. Albumin has been found especially in the so- 

 called red marrow of the spongy bones. Besides these substances, the marrow 

 contains so-called extractive bodies, such as lactic acid, hypoxanthin, and 

 cholesterin, but mostly bodies of an unknown character. 



The diverse quantitative composition of the various bones of 

 the skeleton depends probably on the varying quantities of other 

 formations, such as marrow, blood-vessels, etc., they contain. The 

 same reason explains, to all appearances, the larger quantity of 

 organic substance in the spongy parts of the bones as compared 

 with the more compact parts. SCHRODT has made comparative 

 analyses of different parts of the skeleton of the same animal (dog) 



