PAJITS AND FUNCTIONS. 65 



hdid from these round bodies towards the pelvis, which is a 

 basiii within the soHd of the kidney. We can discern these 

 pipes joining and collecting together into larger pipes ; and, 

 when so collected, ending in innumerable papillee, through 

 which the secreted fluid is continually oozing into its recep- 

 tacle. This is all we know of the mechanism of a gland, 

 i'ven in the case in w^hich it seems most capable of being 

 investigated. Yet to pronounce that we know nothing of 

 animal secretion, or nothing satisfactorily, and with that 

 concise remark to dismiss the article from our argument, 

 w^ould be to dispose of the subject very hastily and very 

 irrationally. For the purpose which we want, that of evinc- 

 ing intention, we know a great deal. And what we know 

 is this. We see the blood carried by a pipe, conduit, or 

 duct, to the gland. We see an organized apparatus, be its 

 construction or action what it will, which we call that 

 gland. We see the blood, or part of the blood, after it has 

 passed through and undergone the action of the gland, com- 

 ing from it by an emulgent vein or artery, that is, by an- 

 other pipe or conduit. And we see also at the same time a 

 new and specific fluid issuing from the same gland by its 

 excretory duct, that is, by a third pipe or conduit ; which 

 new fluid is in some cases discharged out of the body, in 

 more cases retauied within it, and there executing some im- 

 portant and intelligent office. Now supposing, or admit- 

 ting, that we know nothing of the proper internal constitu- 

 tion of a gland, or of the mode of its acting upon the blood, 

 then our situation is precisely like that of an unmechanical 

 looker-on, who stands by a stocking-loom, a corn-mill, a 

 carding-machine, or a thrashing-machine at work, the fab' 

 rie and mechanism of which, as well as all that passes with- 

 in is hidden from his sight by the outside case ; or, if seen, 

 would be too complicated for liis uninformed, uninstructed 

 understanding to comprehend. And wdiat is that situation ? 

 This spectator, ignorant as he is, sees at one end a material 

 ent(^r the machine, as unground grain the mill, raw cot.tfj» 



