BONES, BLOOD. 381 



as the serous and mucors membranes, the cartilages, the bones 

 themselves, which are in fact only cellular tissue impregnated with 

 calcareous salts. Tendons may be viewed as condensed ropes of 

 cellular tissue ; by long boiling in water they melt entirely into gela- 

 tine. 



Bones consist of cellular tissue, as stated, resolvable into gelatine, 

 and of a large proportion of saline earthy matter, consisting princi- 

 pally of phosphate of lime. The presence of this phosphate is not 

 extraordinary, inasmuch as we have found that it forms an element 

 in all the vegetables upon which animals are supported. By boiling 

 bones even reduced to powder under the usual pressure of the atmo- 

 sphere, but a small quantity of their gelatine is obtained ; but by put- 

 ting them into a Papin's digester, and subjecting them to a consider- 

 ably higher temperature than that of boiling water, we can dissolve 

 the whole, or nearly the whole of the animal matter, and leave the 

 earthy parts unchanged ; or by proceeding in another way, by soaking 

 bones for a time in dilute muriatic acid, we can dissolve out the 

 earthy matter, and leave the bone, having its original form indeed, 

 but as an elastic, pliant gristle. 



The relations between the earthy and organic matter of bone, 

 vary with the species, but especially with the age of the animal. In 

 early life the cellular element predominates ; in adult age the salts 

 predominate. We have three analyses of bone, which I shall here 

 present : 



Man. Ox. Ox. 



Cartilage susceptible of change into gelatine 33.3 33.3 50.0 



Sub-phospliiite of lime 53.0 57.4 37.0 



Carbonate of lime 11.8 3.9 10.0 



Phosphate of magnesia 1.2 2.0 1.2 



Soda, and a trace of common salt 1.2 3.4 " 



100.0 100.0 98.3 



Hair has a very complex composition, no fewer than nine different 

 principles or substances having been detected in its constitution ; 

 among the number, mucus, various oily matters, sulphur, and iron ; 

 wool, fur, and horn, are all similar in their composition to hair. 



Bloody in all the higher animals, is a sluggish fluid, of a deep red 

 color ; in many of the inferior tribes, however, such as insects, crus- 

 taceans, and shell-fish, it is limpid, and generally colorless. Under 

 the microscope, red blood is seen to consist of two distinct portions, 

 a serum or whey, in which float a multitude of minute, solid, opaque 

 corpuscles — the globules of the blood of physiologists, particles which 

 have different characters in different classes of animals. 



Blood is a very heterogeneous compound. Left to itself, after 

 being drawn from a vein, it sets or coagulates into a soft gelatinous 

 solid, which by and by begins to separate into two portions, one 

 watery, of a yellowish color, and opalescent, the water, whey, or 

 serum ; another solid, of a deep red or reddish brown color, the clot 

 or coagulum. The watery portion contains a large quantity of albu- 

 men in solution. M. Lecanu, in his analysis of the blood, speaks of 

 as many as twenty-five different substances as entering into its cona- 

 positioQ : 



