FATS. 89 



homogeneous solids. Thus, the sugars of the blood are in solution 

 in water, in company with the albumen, the phosphate of lime, 

 chloride of sodium, and the like ; all of them equally distributed 

 throughout the entire mass of the fluid. In the bones and car- 

 tilages, the animal matters and the calcareous salts are in similarly 

 intimate union with each other ; and in every other part of the 

 body the animal and inorganic ingredients are united in the same 

 way. But it is different with the fats. For, while the three prin- 

 cipal varieties of oleaginous matter are always united with each 

 other, they are not united with any of the other kinds of proximate 

 principles ; that is, with water, saline substances, sugars, or albu- 

 minous matters. Almost the only exception to this is in the nerv- 

 ous tissue; in which, according to Robin and Yerdeil, the oily 

 matters seem to be united with an albuminoid substance. Another 

 exception is, perhaps, in the bile ; since some of the biliary salts 

 have the power of dissolving a certain quantity of fat. Every- 

 where else, instead of forming a homogeneous solid or fluid with 

 the other proximate principles, the oleaginous matters are found 

 in distinct masses or globules, which are suspended in serous fluids, 

 interposed in the interstices between the anatomical elements, in- 

 cluded in the interior of cells, or deposited in the substance of 

 fibres or membranes. Even in the vegetable tissues, the oil is 

 always deposited in this manner in distinct drops or granules. 



Owing to this fact, the oils can be easily extracted from the 

 organized tissues by the employment of simply mechanical pro- 

 cesses. The tissues, animal or vegetable, are merely cut into small 

 pieces and subjected to pressure, by which the oil is forced out 

 from the parts in which it was entangled, and separated, without 

 any further manipulation, in a state of purity. A moderately 

 elevated temperature facilitates the operation by increasing the 

 fluidity of the oleaginous matter; but no other chemical agency is 

 required for its separation. Under the microscope, also, the oil- 

 drops and granules can be readily perceived and distinguished 

 from the remaining parts of the tissue, and can, moreover, be 

 easily recognized by the dissolving action of ether, which acts 

 upon them, as a general rule, without attacking the other proxi- 

 mate principles. 



Oils are found, in the animal body, most abundantly in the 

 adipose tissue. Here they are contained in the interior of. the 

 adipose vesicles, the cavities of which they entirely fill, in a state 



