RESINOUS SECRETIONS. 119 



rnunication with the atmosphere, such as the abdomen, 

 thorax, pericardium, pleura, &tc., and are reflected over 

 the organs which lie in these cavities. The principal 

 use of these secretions is, to furnish these parts with a 

 proper degree o moisture, so that they may glide freely 

 and smoothly over one another. In diseased states of the 

 body, these secretions sometimes accumulate to a pro- 

 digious extent, constituting the disease of dropsy. 



The mucous secretions are a transparent viscid fluid, 

 of a saltish taste, consisting of water and a very small 

 portion of several alkaline and earthy salts. It is poured 

 out from the surface of those membranes whtfh line 

 cavities of the body that have an external communica- 

 tion, as the alimentary canal, air-passages, &.C., serving 

 to protect these parts from the atmosphere, and concur- 

 ring by means of its peculiar properties, in the perform- 

 ance of their functions. It is formed by minute bodies 

 of a glandular character, immediately below the mem- 

 brane called mucous crypto ; sometimes however, it is se- 

 creted from glands of a considerable size, as the parotid 

 and salivary glands in the mouth, which secrete the 

 saliva. 



Of the oleaginous, the principal is the fat which is 

 found in different parts of the body, and always secreted 

 from the cellular tissue. Its chief use seems to be the 

 protection that it gives to the parts where it exists, against 

 the pressure of foreign bodies, as in the sole of the foot 

 for instance, and to give a general rotundity of outline 

 to -the surface. In some cases, as in corpulency, it ac- 

 cumulates without answering any particular purpose ; 

 here the object of th/ secretion seems to be merely to 

 free the blood from its superfluous carbon and hydro- 

 gen. The milk of animals belongs to this class of secre- 

 tions. 



The resinous secretions consist of substances very re- 

 mote from any thing we find in the blood. The princi- 

 pal of them is the bile which has been already described. 

 It is called a resinous secretion, because it contains a 



