Ox\ SYMPATHY AND FASCINATION. 



255 



When the circulation of the blood was first discovered, it was supposed 

 that all these anomalies might fall withm the range of this admirable me- 

 chanism, and might be explained by its operation. Not one of them, how- 

 ever, is capable of such an explanation. JNor is even the difiused redness 

 which uniformly takes place around the nucleus of an inflamed part, in any 

 degree more intelligible or more referable to this principle ; since, in con- 

 sequence of the device of a circulating sj^stem, the vessels in the immediate 

 j vicinity of each other, are as much cut off from all direct communication 

 " as those at the remotest distance ; and only, so far as we are able to trace 

 by ocular experiment, associate by the common current of the blood. 

 That they do, in fact, associate by other means we know : but it is by means 

 altogether concealed from us : it is by what, as already observed, we call 

 sympathy or fellow-feeling ; but what we only call so to express a pecu- 

 liarity of action, the cause of which we are incapable of penetrating. 



There is one curious and highly important discovery in the animal eco- 

 nomy, however, that has been made, or rather, completely established, 

 within the last two or three years, which seems to show that such associate 

 action of parts, at a distance from each other, may be the result of a direct 

 intercourse or medium of communication, though the connecting channel 

 is too subtile for pursuit : for it seems now to be ascertained, as it had, in- 

 deed, been long suspected, though without the proof of actual experiment, 

 that a variety of substances pass from the stomach into the kidneys, appa- 

 rently without entering into the circulation of the blood, by an unknown 

 and even a much shorter course. Now, to the eye of the anatomist, there 

 are no organs more distinct from each other ; they not only lie far remote 

 in situation, but even in different cavities, and are separated by a strong, 

 stout membrane, called the peritonaeum. 



To determine whether such a channel actually exists or not. Dr. Wol- 

 laston introduced into the stomach three grains and a half of the salt 

 called prussiate of potash ; the presence of which, in almost all kinds of 

 colourless fluids, is capable of detection to the utmost nicety, by mixing 

 with them a small portion of solution of iron, the colourless compound 

 being immediately marked with a blue tinge. The above quantity was 

 given to a healthy person, about thirty-four years of age, and was repeated 

 every hour to the third time. The natural secretion from the kidneys 

 being tested every half hour, was found in two hours to be slightly dyed, 

 and at the end of four hours to afford a deep blue. At this period, just 

 one hour after taking the last dose, and when the blood-vessels might be 

 supposed to be fully impregnated with the material, if it passed to the kid- 

 neys, through this conveyance, blood was taken from the arm, and allowed 

 to coagulate, so that the serum or limpid part of it might be fuily sepa- 

 rated. The presence of the prussiate was then endeavoured to. be dis- 

 covered, my means of the solution of iron, but without the least effect, for 

 the serum still remained colourless. And in other experiments of a simi- 

 lar kind, made both by Dr. Wollaston and Dr. Marcet, it was satisfactorily 

 ascertained, that the prussiate of potash, though it found its way readily 

 to the kidneys, did not exhibit any trace of its existence in the fluid of 

 any other organ whatever, any more than in that of the blood ; as the 

 saliva, the mucus of the nostrils, or the limpid discharge produced by 

 blisters. Mr. Home has since shown, that rhubarb introduced into the 

 stomach in like manner finds a path to the kidneys, apparently without 

 passing through the circulating system.* 



* The only mode by Tyhich the present writer can conjecture the possibility of these 



