of bile, therefore, is found in the gall bladder, there may have been an increased excretion of it, a preternatural absorption having been excited. So that it may admit of a question whether the colour of the skin, in the yellow fever, is owing to this, or if the idea of it given in the text[104] is more just; but in either case it seems probable that the extreme tendency to putrefaction in the whole body is owing either to the presence of bile, in consequence of absorption, or the retention of something in the blood from a defect of its secretion. This reasoning concerning the bile in hot climates may, in some sort, be illustrated by what happens to the urine in cold climates. The urine is the vehicle of an excrementitious part of the blood, of which an increased proportion is generated in certain fevers, and if it is thrown out in the form of high-coloured, turbid urine, the fever will most probably be slight and short; but if it becomes pellucid, or _crude_, as it is called, the general derangement will be increased, the fever will be more violent and dangerous, and the first sign of returning health will be a turbid appearance and sediment. If the reasoning in the above discussion should appear to some readers unsatisfactory, or ill connected, I can only say that if it is deserving of this character, I am willing to have it considered not only as an illustration, but an example of the nicety and fallacy of theoretical disquisitions. [104] See page 437-8. [105] I have been very cautious of admitting any theory into this work; but I cannot help adopting the doctrine of my much-valued master, Dr. Cullen, on this point, viz. that a great part of the symptoms of fever arise from reaction, or that effort which nature makes to overcome the morbid cause. I am happy in any opportunity of acknowledging my obligations to this learned professor, to whom the medical world in general is so much indebted, as well for the rational views of the animal œconomy, which he teaches, as for that spirit of study and inquiry which he infuses into the minds of his pupils. [106] M. Desportes, who wrote a treatise on the diseases of St. Domingo. [107] There is a difference in the appearance of the blood when sizy, perhaps not sufficiently insisted on by practical writers; for though there should even be a very thick buff, yet, if the surface is flat, and the _crassamentum_ tender, no great inflammation is indicated, in comparison of that state of the blood wherein the surface is cupped, the _crassamentum_ contracted so as to afford the appearance of a large portion of _serum_, and where it feels firm and tenacious, though perhaps but thinly covered with buff. This is a distinction well worth attending to in practice; for it is in these last circumstances that blood-letting gives most relief, and where the patient will bear the repetition of it with most advantage. [108] See the same observation in Mr. Hume’s Essay on this Disease, published by Dr. Donald Monro.