OF THE CAPILLARY VESSELS. 265 



rand, admit, on the contrary, the opinion that it is by laternal 

 pores, organically arranged, that secretion or exhalation oc- 







curs. 



Hunter had even admitted that it was by pores or inorganic 

 interstices that secretion took place, precisely in the same 

 manner as transudation in the dead body. Hewson and Bi- 

 chat have controverted this opinion. 



The real passages, however, of exhalation or secretion are 

 entirely unknown. All we know on this subject, is merely 

 this, that in the living body, fluids issue under the form of 

 vapour from all points of the capillary system; and that seve- 

 ral are observed in a liquid form, or even more or less con- 

 crete; while in the dead body fine injections, in passing from 

 the arteries into the veins, ooze out on the surface of the skin 

 and mucous membrane, in the mucous and cutaneous follicles, 

 in the excretory ducts of the glands, on the free surface of the 

 serous membranes, and in the mucous, areolar or cellular 

 substance, which constitutes the solid mass of the body; but 

 never, and nowhere are there seen ramuscules arising from 

 capillary net-works and terminating by an open extremity. 

 The passages of exhalation or secretion are therefore un- 

 known. It is very probable that it occurs through the solid 

 and porous substance of the body. Secretion, fiawever, is an 

 organic or vital phenomenon entirely different from transuda- 

 tion in the dead body, as is demonstrated by the difference 

 which the various secreted humours present, and the differ- 

 ences of quantity of these humours. The names of exhaling 

 or secreting vessels can only therefore, designate the unknown 

 passages through which the molicules, formed by the mat- 

 ter of the intrinsic and extrinsic secretions, issue from the 

 circulation. 



393. Nearly the same may be said respecting the passages 

 or mechanism of absorption. The absorbent vessels, accord- 

 ing to the idea entertained of them, are radicles open at one ex- 

 tremity, similar to the puncta lachrymalia, and continuous at 

 the other, either with the venous and lymphatic net-work, or 

 with the lymphatic vessels alone, or with the veins alone, of 

 which they are thus the origin. Now, neither these canals 



