276 INFLAMMATION not characteristic of inflammation, but the idea that such is the case has led to the most mis- chievous results in practice." He maintains that irritation of texture, contraction or dila- tation of the blood vessels, capillary hremor- rhage, serous effusion which constitutes dropsy, and stoppage of the sanguineous circulation, are only accompaniments of inflammation ; and that its essential condition is exudation of liquor sanguinis. Dr. Alison observes that a precise notion of inflammation is obtained by including with the four cardinal symptoms a tendency to effusion of new products capable of assuming the form of coagulated lymph or purulent matter ; but Dr. Bennett maintains that the tendency cannot be separated from the act itself, and that it is only when the exuda- tion has taken place that there is proof that the tendency existed. The objection to this view is that inflammation may take place in non- vascular parts ; to which Dr. Bennett replies that the changes which occur in these parts when irritated are widely different from those in vascular parts, and should not be confound- ed ; and moreover, that what has been called parenchymatous inflammation is not true in- flammation, which term should only be applied to that perverted action of the vascular tissues which produces an exudation of the liquor sanguinis, and that other results of irritation are simply congestion, or increased growth or hypertrophy. As to the terminations of in- flammation, Dr. Bennett divides them into two, depending upon whether the exudation lives or dies. If it continues to live, it constitutes a molecular blastema, in which new growths, temporary or permanent, spring up according to the molecular law of development, such as pus and adhesive lymph. When, on the other hand, the exudation dies, three things may fol- low : 1, rapid death, with chemical decomposi- tion, producing mortification or moist gan- grene; 2, slow death, with disintegration of the tissues, causing ulceration ; 3, what may be called a natural death, in which the exudation is broken down, liquefied, and absorbed, or in other words, resolution. When the exudation lives, it undergoes vital transformations which are greatly influenced by the condition of the system, whether it is healthy or diseased. In the healthy condition, when the exudation takes place on serous membranes, like the pleura, it has a strong tendency to form fibrous tissue ; when it occurs on mucous membranes, or in areolar tissue, it is generally converted into pus corpuscles; when it occurs in dense parenchymatous organs, such as the brain, it has a granular development ; and when it is poured out after wounds or injuries, the super- ficial portion is transformed into pus corpus- cles, while the deeper seated is converted by means of nuclei and cells into nucleated and cell fibres, which ultimately form the cicatrix. The microscopic examination of a recent exu- dation of liquor sanguinis will reveal the ap- pearance of bundles of minute filaments min- gled with corpuscles. The filaments are formed by a simple precipitation of the molecules, like those which are developed in the huffy coat of the blood, and are from TT jnnF to 3-^,^5^ of an inch in diameter. Bundles of them cross each other, and in time assume the appearance of dense fibrous tissue. The corpuscles at first are transparent, but soon become distinct, and are seen to be composed of a cell wall enclosing from three to eight granules. They vary in size from -rjVr to -nsW> an d the granules from Ti.&TTir to TT!F!T of an inch m diameter, and are termed by Dr. Bennett plastic cor- puscles. They are not pus, although Lebert called them pyoid, and it is generally be- lieved that they are an intermediate or ar- rested stage of the degeneration of plastic lymph from its fibrillated development to pus. These plastic corpuscles after a time mostly disappear, some remaining in the form of per- manent nuclei. After a time the surface of the exudation becomes villous, and loops of blood vessels penetrate the villi, by which the serum separating the surfaces is absorbed, so that they come together and unite, forming dense adhe- sions, which are often found in post-mortem examinations after inflammations of serous membranes. When the exudation takes place upon a mucous membrane, it may have the form of a fibrous mass, as in croup or diphthe- ria, but more often that of an opaque creamy fluid called pus. When it is poured into the meshes of the areolar tissue, or into the sub- stance of the brain, it forms abscess. Pus cor- puscles are of a globular form and yellowish color, varying from ^Vr to TjVjr ' an mcn m diameter. They are composed of a cell wall containing from two to five granules, which are about EI/OO of an inch in diameter. When a microscopic examination is made of a recently formed granulation on a healing wound, there will be observed around the looped extremities of the capillary vessels fibrous tissue in the process of formation containing plastic cor- puscles, while pus corpuscles will be found de- veloped on the surface. As the fibrous tissue becomes more dense the pus diminishes, and at last ceases, the fibrous tissue attaining a cer- tain growth, and after a time contracting and forming a cicatrix. All pathologists agree very nearly as to the changes which are here described, but many, among them Virchow, Billroth, Simon, and Sir James Paget, believe that inflammation is not restricted to one act ; that congestion and determination of blood may be considered its first stages ; and that it may exist and pass away without exudation. They ask, if inflammation is produced by irri- tation, when this is in process of operation, where shall the dividing line be placed between the departure from health and the commence- ment of inflammation ? It is also objected that the web of a frog's foot, as being a part of a cold-blooded animal, is not a proper sub- ject for the experiment, and accordingly a bat's wing has been substituted. Sir James Paget
