sic properties of the mental and tabes, atrophy, scurvy, and various species of gangrene. III. IntrinAnd if it become once impregnated with a peculiar taint, it is wonderful to remark the tenacity with which it re- blood. tains it, though often in a state of dormancy or inacti- Transmits vity, for years or even entire generations. For as every corporeal germ and fibre of every other part is formed and regene. taints to nerated from the blood, there is no other part of the subsequent system that we can so well look to as the seat of such taints, or the predisposing cause of the disorders I am now alluding to; often corporeal, as gout, struma, phthisis; sometimes mental, as madness, and occasionally both, as cretinism. generations. Hence supposed to be As taught, especially by Mr. J. It is hence the blood has been supposed to be alive: a belief of very high antiquity, and which has been alive. warmly embraced by Dr. Harvey and many others of the first physiologists of modern times. It was a favourite opinion of Mr. John Hunter, and runs through the whole of his doctrines. "That the blood", says he, "has life, is an opinion I have started above thirty years, and have taught it for near twenty of that time in Hunter. my lectures. It does not, therefore, come out at present as a new doctrine; but has had time to meet with considerable opposition, and acquire its advocates. To conceive that blood is endowed with life while circulating, is, perhaps, carrying the imagination as far as it well can go; but the difficulty arises merely from its being a fluid, the mind not being accustomed to the idea of a living fluid."* The experiments and train of reasoning he urges in favour of this opinion are highly ingenious and peculiarly strong. And, though they may not be demonstrative of a vital and energetic essence separate from the blood itself, but inherent in its substance, and controlling its motions, they seem very clearly to show that the blood is endowed with peculiar powers; and that, as matter at Influenced large is subject to the laws of gravitation, so the matter by the laws of the blood is subject to the laws of instinct. We may * On Blood, p. 77. of instinct. III. Intrinsic proper ties of the blood. Instinct simple life operating by the exer cise of its own laws. Living prin ing to Pring, in morbid se cretions and animal poisons. here add, in favour of Mr. Hunter's opinion, the following two corollaries of Dr. Philip, deduced from a large field of experiments. "The power of the bloodvessels, like that of the heart, is independent of the nervous system. The blood-vessels can support the motion of the blood after the heart is removed."* Admitting these deductions to be established, the power here referred to, and capable of influencing the blood or the blood-vessels, separately from that of the heart, and of the nervous system, must be the power of simple life, or of instinct, which is simple life operating by the exercise of its own laws. This view of the subject has of late, however, been carciple accord- ried by Dr. Pring to an extent far beyond what Mr. Hunter at any time contemplated. For Dr. Pring not only supposes the blood to be alive, and to communicate life to the sentient and healthful parts of the system, but to its insentient and diseased elements as well; and that the matter of animal poisons, derived from the blood, are themselves also living bodies, acting specifically by the vital but discrepant properties they are endowed with. And he thinks that hereby "a distinction may be furnished between the contagious and infectious diseases"†. Phil. Trans. 1815, p. 445. † Principles of Pathology and Therapeutics, &c. By Daniel Pring, M.D. 8vo. 1823. CLASS III. НЕМАТІСА. ORDER I. PYRECTICA. Fevers. HEAT AND NUMBER OF THE PULSE PRETERNATURALLY THERE is no complaint so common as fever; none in which mankind, whether professional or laical, are so little likely to be mistaken, and yet none so difficult to be defined. In reality, no writer seems to have been fully satisfied with his own definition; and it is not extraordinary, therefore, that he should seldom have given satisfaction to others. The difficulty proceeds from the complexity of the symptoms that enter into the character of a fever; the contrariety of many of them to each other in different stages of it; and the occasional absence of some that, in other instances, appear to constitute its leading features. "Febris", says Professor Frank, "certorum potiùs morborum UMBRA quàm ipse morbus est. • De Curand. Hom. Morb. Epit. 1. p. 2. 4 Tom. 8vo. Mannh. 1792. ORDER I. Pyrectica. Fevers. of fixing divisions and generic names. There are also two other difficulties of considerable magnitude that the nosologist has to contend with in Difficulty laying down a clear and perspicuous survey of fevers; and that is, their division or collocation, and their generic names. But as I have already pointed out these difficulties, and the means by which they are attempted to be remedied under the present arrangement and nomenclature, in the running commentary to the order before us in the volume of Nosology, I shall beg to refer the reader to the observations there laid down, and shall subjoin only one or two additional remarks upon the same subject. Heat and pulse not always augmented in fever. Although the number of the pulse as well as the heat is preternaturally augmented in almost every case of fever, an extraordinary instance is sometimes to be met with that opposes the general law, for the most part dependent, I believe, on a great and sudden oppression of the brain; an explanation which withdraws the anomaly, and accounts for the ordinary increase of pulsation as soon as such oppression is removed. Thus, in the yellow fever of Antigua in 1816, the pulse, as Dr. Musgrave informs us, was, in one instance, under forty-four. "We almost fancied", says he, "this unusual softness might be constitutional: but, on opening a vein, it greatly increased in frequency; and, after the loss of a considerable quantity of blood, it numbered eighty, with nearly complete relief from every uneasy sensation."* In such cases, the heat of the system usually exhibits as little febrile augmentation as the pulse: for as the former is the result of increased action, till such increased action takes place, the heat, as in the first stage of the paroxysm, may continue even below the natural standard. Ordinarily, however, the heat is considerably heightened, insomuch as in some instances to reach 108° Fahrenheit, which however is the utmost point it has ever been known to attain in fever. • Trans. Med. Chir. Soc. Vol. ix. p. 133. ORDER I. Fevers. There is a still more curious variation from the gene ral law, which is sometimes, though very rarely, found Pyrectica. to take place, of which Schenck gives a single example Instance of that occurred in his own practice; I mean, a reversed hot fit preceding cold. order of the symptoms of the febrile paroxysm, and an appearance of the sweating stage before the shivering and hot fit*. To provide for these extraordinary and anomalous incidents by any definition whatever, is beyond the power of language. They must be left to themselves, and will rather confirm than disturb the definition now offered, agreeably to the maxim of the Schools-exceptio probat regulam. down the with former In dividing fevers into distinct genera I have taken Principle the line of demarcation from the character of their du- adopted by ration, as limited to a single paroxysm; as composed of in laying numerous paroxysms, with intervals of intermission or genera of perfect apyrexy; as composed of numerous exacerba- fevers. tions, with intervals of remission, or imperfect apyrexy; and as composed of a single series of increase and decrease, with a mere tendency to intervals of remission, without perfect apyrexy at any time. Other nosologists Compared have drawn their generic distinctions from other circum- principles. stances; as their disposition or indisposition to putridity; their inclination to a sporadic or an epidemic character; the vigour and violence, or weakness and debility, of their action; or, in the language of Dr. Darwin, the nature of their influence on the sensitive or irritative fibres of the animal frame. The most obvious mark, however, and that which has been most generally approved, is the character of duration assumed in the arrangement before us. To all the rest there are greater or less objections, which, as I have already examined them in the comment just referred to, need not be repeated in the present place. Regulated, therefore, by the principle before us, fever admits of the four following genera: * Lib. vi. Obs. 34. |