forsaken by the organizing principle, degenerate in their organic formation, and their organic chemical blending; whilst those in contact with the living surfaces of the body, proceed in their further organization: thus, by the death of the former, is given life to the latter (mors vitæ origo.)

Upon the free exudation-corpuscles first appear delicate radiating lines, which divide their periphery into six or eight (rarely more) segments: these lines become more decided, and the capsule appears as if torn, though without any solution of continuity. In some even the nucleus seems inclined to break into from two to four pieces. At the same time the originally reddish-yellow fluid fades, the divided segments of the capsule and the divisions of the nucleus, which were distinctly linear, become rounded into cohering granules, whilst the now perfectly formed pus is of a greenish colour. The true pus-corpuscles thus formed, are still here and there connected together, (the pus-membrane,) like the cells of tessellated epithelium; are specifically heavier than the serum; appear under the microscope somewhat larger than lymph-exudation and blood-corpuscles (from 0 to 1 of a Paris line in diameter;) are of a yellowish colour, and mingled with oil-drops and albuminous granules, with which last they are commonly besprinkled, and which are by many considered as integral parts of the corpuscles, they overlooking the usual large granules which in their connexion with the pus-corpuscles are so attached that the latter at first appear as lenticular, or cake-like quilted cushions. Subsequently the granules separate still more, so that the corpuscles are resolved into their elements; old pus therefore consists for the most part of these more or less isolated granules. *** The younger the pus, the greater the quantity of fibrin (transitioncytoblasts) and the older it is, the more fat does it generally contain. Thus, in the degeneration of its organization, from its commencement to its perfection, is it remarkably opposed to chyle, in reference to its organic and chemical relations." (pp. 47, 48.)

"False Pus. Secreted and exuded fluids very frequently occur in man and beasts, which without closer that is, microscopic-examination, may be taken for pus, because they look very like it, and chemically often do not differ much from it, and yet are produced in another way, and are of different nature. On the contrary, substances are deposited and thrown out which seem very different from pus, and yet are either true pus, or very nearly allied to it.

"It is the above-described fluid alone, the true or proper, the so-called laudable pus, which is a necessary condition of reproduction: therefore I call it reproductive pus; and, as the corpuscles usually consist of seven granules, they may also be called septengranular pus-corpuscles. Previous to their division, these corpuscles always belong to the nucleated corpuscles; they are degenerating cytoblasts. In this constant quality of the true pus-corpuscle is the most certain criterion for distinguishing pus from other more or less similar fluids; and that fluid which contains no such corpuscles, or with them any corpuscles or deposit which do not exist in the pus of healthy wounds, is either not pus, or not pure pus." (pp. 53, 54.)

The following are TRAVERS's views on the constitution of pus :-" Pus, I believe," says he, "to obtain its characters of consistency, opacity, and colour after exudation, and to consist of the superfluous or waste lymph which has been separated during the adhesive stage from the mass of blood held in solution by the serum, being thus a chemical modification of the constituents of the liquor sanguinis; in short, the latter fluid deprived of its original character and property of spontaneous coagulation. Pus particles resemble those of lymph seen in the vessels uuder inflammation, except that they appear broken down and partly dissolved in their texture instead of compact and of less regular figure; and, if when suspended in a drop of fluid, compared with the elastic blood-corpuscle, to which they bear no analogy whatever, utterly inert and devitalized. We never see pus in the blood-vessels but in fatal phlebitis, and, if introduced into the circulation by injection, it is destructive to life. Although, therefore, a clean-wiped granulating surface soon presents a covering of pus, it is exuded as a colourless fluid of a more dense and unctuous consistence than serum. Its appearance is simultaneous with the disappearance of the lymph-particle from the veins, the suppurative action being determined, or, in other words, the separation of the proper lymph-particle put an end to by its sufficient deposit in granulation, and the inflammatory nisus still prevailing from the continuance of the irritation, for no imperfect state can be perpetuated; the superabundant lymph-particle, at no time coloured, along with the permanent fluid or serum of the blood, is strained off through the pencils, forming the terminal loops of the granulation. Thus is obtained the twofold purpose of relief to the loaded capillary circulation, and a bland and homogeneous protecting fluid for the granulation during the period of its growth up to that of final organization. When the rudimental fibrin is no longer needed for the new structure, it is used, as in nature all remnants are, for

a new but not less important purpose, the preservation of that structure. Pus is as necessary to the maintenance of granulation as lymph was to its formation; but a change is necessary to fit it for its new function, and this is provided for by a new arrangement of a new action of the secreting capillaries, and a chemical change, which destroys its vital property and amalgamates the separated lymph-globules with the serum of the blood. The precedence of adhesive to suppurative action is sufficient to render presumable a necessary connexion between the lymph separated during the first process, and afterwards disappearing, and to explain the invariableness of this relation in the order of their appearance. There is no analogy between the effusions of serum or of liquor sanguinis incidental to primary wound or injury of any kind and pus, yet the ingredients of the two latter are the same: it is by the combinations of a vital chemistry that their appearance and sensible properties differ, and this we are capable of imitating. If this theory be admitted, it will explain the appearance of pus in the absence of the especial granular structure or distinct pyogenic membrane, as seen upon mucous, serous, and synovial surfaces and canals; and, even in the absence of fibrinous exudation, as in certain modes of inflammation, where the habit of the parts or the character of the inflammation renders them incapable of carrying on the adhesive action, or that action is by violence interrupted. Puriform mucus, muco-purulent secretion, are terms in common use, indicating the transition stage witnessed in these cases; so also the modifications of colour, consistence, and purity are explained, which are conveyed by the terms sanious, flaky, or whey-like, ichorous, &c., and the improvement of the secretion by elaboration from that of fistula and sinuses to the 'pus laudabile' of old authors concurrent with the improved vitality of the granulations, meaning a fuller proportion of the lymph-particle to the serum, and vice versa, its degeneration in enfeebled and sinking states of the system. Thus also is explained the effect of inordinate and excessive suppuration to superinduce hectic, from the excessive withdrawment of that ingredient which forms the nutrient and restoring principle of the blood. *** The conversion of the blood-corpuscle into the pus-corpuscle is a notion altogether gratuitous and unsupported either by appearance or probability; and, to my mind, the above is a theory more reconcilable with all the circumstances attending its origin than that which supposes de novo formation of the pus globules. But the wounds of coldblooded animals not being subjected to the true suppurative process, nor those of mammalia and birds disposed to free suppuration, there appears to be insuperable difficulty in establishing this theory by actual demonstration." (pp. 172, 6.)]

14. The nature of the pus varies considerably according to the nature of the parts in which it is formed, according to the constitution of the person, according to the degree and character of the inflammation; it may be changed by other fluids, mingled with it. We distinguish good creamlike, uniformly consistent, yellowish white, inodorous pus, (pus bonum et laudabile, Lat.,) thin, mucous-like, serous, grayish, greenish, brownish, and more or less fetid pus (sanies, ichor, Lat.; Jauche, Germ.) (1). These varieties of pus, as well as the fluid products of inflammation especially, depend merely on the different proportions of the materials composing it. All these products are derived from the blood, and in them are found all the same materials as in the blood, excepting fibrin. Thus is it clear why chemical and microscopical examination cannot ascertain any determinate difference between the products of inflammation and the serum of the blood, the mucus, the serum from dropsy, the yellowish white fluid (materia puriformis) poured out from inflamed mucous membranes (2); the thin, lymph-like fluid which exudes from inflamed serous membranes (3) and the various kinds of pus appear to be compounded in the same way. Their difference consists only in the different proportions of the several substances, in their disposition to organization, and in the greater or less advanced degree of plastic activity (4).

The presence of globules in the serum has been long since proved by BAUER and FARADAY (a), as also by MANDT and others in the various effusions and serosities which occur in the cellular tissue and in the serum of dropsy; but the albumen in pus is in (a) See HOME on the Conversion of Pus into Granulations or New Flesh, in Phil. Trans. 1819, p. 2.

a higher degree of coagulation, is opake, of tolerable consistence, and coagulates less by warmth, and by the concentrated acids. The difference between creamy, consistent, and thin serous pus depends entirely on the different proportions of the fluid and of the pus-globules. BONNET, (as above,) who seems not to know the pus-globules, derives this difference from the greater proportion of the emulsive fat in the former and its smaller proportion in the latter. We may give every kind of pus that semi-transparency, that stringy character, that adherence of its parts which seem especially proper to mucus, if we mix and shake it up with a solution of hydrochlorate of ammonia, whereby the proportion of one of its components is increased. The consistence of pus is to a certain extent influenced by the length of time it has been retained in the body, the absorption of its fluid part thereby occurring, and in suppurating surfaces perhaps also by the influence of the air, as, in the latter case, when the pus is washed off clean, a clear serous fluid is always observed to ooze up. In this manner we may judge of the various tests of pus, for the purpose of distinguishing it from mucus. According to GRASSMEYER (a), if pus be mixed with twelve parts of distilled water and one part of liquor potassæ, a viscous transparent jelly capable of being drawn into thread is formed, more quickly or more slowly according to its different composition. According to GRUITHUISEN'S microscopic examinations (b), pus exhibits white spherical granules slightly dotted upon the surface, which after some hours fall, and even preserve their round form in pus which has been dried and again moistened. In mucus these granules only appear when it is previously thinned with pure fluid: the granules in mucus are less numerous and dark-coloured. FISCHER (as above) holds it best, in order to determine the presence of pus and mucus, to mix and shake together the questionable matter with two or three parts of liquor potassæ or liquor ammonia caustici, and then to add hydrochlorate or nitric acid to neutralisation. If it contain pus, there will be produced by the continued addition of the acid a whitish flocculent sediment.

[(1) Ichor," says GERBER," has very various colours, and is generally more fluid than pus. The ulcer is a wound with a dead surface incapable of throwing out or organizing plastic lymph, bedewed with a depraved serum (ichor) destructive of every exudation. This ichor acts injuriously on the ulcer, destroying it and eating into the neighbouring vessels: hence the discharge of small quantities of blood, which is immediately discoloured in the ichor, and so much changed that the liquor sanguinis rarely coagulates, save in granules; the blood-corpuscles appear puffed up, corroded superficially, divided into irregular pieces or even shrivelled up. The blood-corpuscles thus altered are denominated ichor-corpuscles: they are commonly covered with granules attached to them or partially lying on them; their character is ascertained in the discharge of glanders which principally consists of them." (p. 56.)

(2)" Puriform mucus, secreted in the last stage of catarrhal affections, varies according to the extent of reproduction which the affected mucous membranes require. Should the mucous glands and follicles be altered in a less degree than the cuticle, which after catarrhs is always produced afresh, then the mucus, besides the usual mucous corpuscles and granules, contains, instead of the usual older elements of the epithelium, which are large, squamous, granulated, epithelial cells or cylinders, a large addition of newly-formed small lenticular cells, in which the nuclei are often recognised with difficulty; hence rendering them very like large exudation-corpuscles. Sometimes among these young epithelial cells true pus-corpuscles are observed, when any part of the mucous membrane needs reproduction." (p. 54.)

66

(3) In serous exudations," he proceeds, "it is usual to find albuminous granules in albuminous fluids, and, if a great part of the serum be again removed by absorption, the crystals of different salts. ***After plastic exudations, a yellowish turbid fluid is found in the affected cavities containing fine flocculi of a pale yellow colour: these are partially precipitated upon the walls of the cavity, which appear bestrewed over the whole extent of the exudation." (p. 42.)

The distinguishing characters of true Pus and Ichor have been already mentioned. (4) This statement of our author, "that chemical and microscopical examination cannot ascertain any determinate difference between the products of inflammation and the serum of the blood," &c. &c., and that "their difference consists only in the different proportions of the several substances," &c. &c., is rather too hasty, as the extracts just quoted from GERBER on the subject show that there is a well-marked distinction among them.-J. F. S.]

15. Pus cannot be produced without inflammation; but the latter may (a) Abhandlung von dem Eiter und den Mitteln, (b) Naturhistorische Untersuchungen über den ihn von allen, ihn ähnlichen Flüssigkeiten zu Unterschied Zwischen Eiter und Schleim. Münunterscheiden. Götting., 1790. chen, 1809.

exist in so slight a degree as to be scarcely, or even not at all, observable, and, on account of the too slight vital activity of the organ, the low state of the nervous power, and of the plasticity of the blood and the diseased diathesis, a serous thin pus is produced without the appearances of inflammation being manifest. The circumscription also of the pus in a definite cavity proves that inflammation must have been present. Abscesses thus originating are called Cold Abscesses, Lymph Abscesses (kalte Abscesse, Lymph Abscesse, Lymphgeschwülste, Germ.; Abcès froid, Fr.) They are always the consequence of a general cacochemic or dyscracic affection, and arise either spontaneously and commonly in many places at once, or are produced by an external injury.

We may very properly apply with WALTHER the name Diathesis purulenta to that general condition of the body which is the ground of these abscesses; but it is improbable that pus can be formed in the blood itself by decomposition within the vessels, and that the blood can be immediately converted into pus. The circumstance of pus having been found in the blood, cannot form a ground for this opinion, as this, if the walls of the veins are not inflamed, intimates merely the absorption of the pus which has been found as well in the lymphatic vessels as in the veins (a). The so-called abscess of congestion, in which the source of the pus, mostly the carious destruction of bone, is more or less distant from the collection of pus upon the surface of the body, must be distinguished from cold abscess: this, however, will be considered in several places.

16. The commencement of cold abscess usually sets in, without any sensibly perceptible local appearance, with diminution of appetite, general uneasiness, slight fatigue, disturbed sleep, and so on. Next there appears on some part of the surface of the body, (where many patients fancy they have had a sort of prickly sensation,) most commonly between the shoulderblades, on the chest, on the loins, on the upper part of the thighs, a little, not discoloured, elastic, scarcely fluctuating swelling, which is not painful, and at the utmost gives the patient an obscure sensation of tension and weight. Gradually the swelling enlarges, often to a considerable size, the fluctuation is distinct, and the symptoms of a disturbed assimilation become more marked. After a shorter or longer time, the swelling begins to be painful, the skin covering it reddens, becomes tense, the general appearances mentioned are more decided, febrile action sets in, and the whole countenance of the patient is cachectic. The skin, continuing to thin, at last breaks, and a quantity of thin, pus-like, often completely putrid and stinking, fluid is evacuated, followed by a clear discharge, which, if the neighbouring bone be destroyed, is of an ichorous character. By this great loss of the juices, and by the colliquative sweats and purging, which soon set in, the powers of the patient are speedily broken up.

[The cold abscess here described must be confounded neither with HUNTER'S "collections of matter without inflammation," (p. 390,) which are, as he says, of a scrofulous nature, and very different from that under consideration, nor with "the cold abscess of the surgeons of the Saracen school, the chronic abscess of modern surgeons," mentioned by BOYER and CRAIGIE (b) (pp. 43-163), and caused by chronic inflammation.

The true cold abscess, which CHELIUS has here well described, is, I believe, very rare. I have recently had a case of which the following is a brief account:Philip Coyne, aged 26, admitted under my care,

August 27th, 1844. He was very irritable, complained of much lassitude and debility, and that he had some difficulty in passing his water, for which about a fortnight ago he had a catheter passed, but had not been since inconvenienced. He did not, upon examination, appear to have any surgical complaint; but, as he had been ill-fed, and suffering (a) See CRUVELHIER, Anatomie Pathologique,

vol. i. p. 200. GENDRIN, as above, p. 22.

(b) Elements of General and Pathological Anatomy. Edinburgh, 1828. 8vo.

privation for some little time before his admission, I kept him in the house for charity's sake, though I suspected he was feigning illness. He, however, grew worse, had a hot skin, with much perspiration, loss of appetite, pains in his joints; and, again complaining of difficulty in passing his water, which was not, however, caused by any stricture, I considered therefore his case to be medical, and, on

September 3rd. He was transferred to Dr. Burton's care, who treated him with sulphate of quinine and citrate of iron, with a colocynth and calomel pill occasionally. He continued growing worse, and, on

September 10th. I was requested to see him again, when he still complained of difficulty in voiding his urine, and had a largely diffused swelling extending over the whole right inguinal region, without redness, with little pain, but with distinct fluctuation, and extending down behind the right spermatic cord into the scrotum, which was so little protruded that the swelling there was only accidentally discovered. The swelling in the groin, which was only noticed yesterday or the day before, is quite subcutaneous. I made a puncture a little above the middle of Poupart's ligament, and drew off a pint of healthy, sweet-smelling pus, and the swelling in the purse subsided as it flowed. Half a grain of acetate of morphia nightly was ordered, to give him rest, which he much needed.

On the following day he was better, and a mutton chop with porter daily was ordered. September 13th. There is little discharge from the puncture; but he now points to another subcutaneous abscess without redness and with little pain, beneath the spongy body of the penis, which was opened, and a table spoonful of good pus voided. He complains of much tenderness in the left knee, to which bran poultice was ordered.

September 14th. But little discharge from either opening. Since yesterday a large diffused swelling has presented on the left side of the chest, below the arm-pit, without redness, but tender and with indistinct fluctuation.

September 16th. The abscess just mentioned was opened, and four ounces of good pus discharged. He now points to another diffused swelling, without redness, on the front of the right shoulder, which fluctuates indistinctly. There is but little discharge from the groin. For the last two days he has been taking ammoniated citrate of iron, five grains, with a drachm of compound spirit of ammonia in infusion of quassia thrice a day. I ordered him, in addition, half a pint of port wine, as he sweats very profusely, has a quick, feeble pulse, and is very weak and thirsty.

September 17th. The abscess on the shoulder was punctured, and about an ounce of pus discharged. The sweating still continuing, he was ordered to take of dilute nitric acid ten drops in infusion of roses, thrice a day.

On the following day, being nauseated and a little sick, a draught of peppermint water with a drachm of sulphuric æther was ordered, but it did not do him much good, and, on September 19th. He was ordered, instead, five minims of dilute hydrocyanic acid in water, a mustard poultice to the region of the stomach, and four ounces of brandy daily, instead of the wine. The abscesses on the shoulder and chest discharge freely; but those below are healed.

September 27th. On the whole, somewhat better; but the discharge is still very profuse. There is now much fluid in the mucous bag behind the insertion of the m. rectus femoris, and the knee is very tender: the bran poultice was discontinued, and a blister ordered, with a poultice afterwards.

October 8th. Has not materially improved, and is now attacked with diarrhoea. Ordered fifteen minims of nitro-muriatic acid three times a day.

October 9th. The diarrhoea continues, and is now accompanied with sickness. The acid to be left off, and in its stead fifteen grains of carbonate of potass, with compound tragacanth and acacian gum powder in clove water, with compound spirits of ammonia and tincture of cardamoms, every four hours.

October 21st. On the whole, better; but little discharge from the abscesses; the knee unimproved.

October 28th. Another blister applied to the knee.

November 2nd. The knee considerably swollen and painful; an issue to be put in above and below the joint.

Having got into a very awkward and uneasy posture, his left leg being laid completely on the outside, and not moveable without great pain, I thought it advisable to get the limb on an amesburg, and gradually from day to day to raise it up till on the heel. This was effected in the course of a few days, and rendered him much more comfortable, and the knee diminished in size, as the issues began to discharge. He never, however, rallied, but gradually continued drooping, became very excitable and so weak that he continually passed his motions beneath him. A patient's death near him had very much