Licence: Public Domain Mark
Credit: Surgery. Source: Wellcome Collection.
Provider: This material has been provided by the Augustus C. Long Health Sciences Library at Columbia University and Columbia University Libraries/Information Services, through the Medical Heritage Library. The original may be consulted at the the Augustus C. Long Health Sciences Library at Columbia University and Columbia University.
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![some do not, the difficulty is great in giving a clear, logical definition to this condition, although we easily recognise the combination of processes which are taking place in the tissues. I should regard inflammation as a modification of the normal physiological processes in the various tissues of the body, resulting from the ap])lication of some irritant, mechanical or chemical, to the part—or, as Virchow terms it, 'a disorder of nutrition '— the ])rocess in many instances being followed by the formation of a new material of a less highly organised nature than the original tissue in whicli the inflammation has taken place. Inflammation is attended by a local disturbance of the circulation, with, in the first instance, an increased flow of blood into and through the part. There are, however, other conditions in which there is also this same local disturbance, with increased blood flow, and these conditions are known as Active cotii^estion^ Active hypercemia, or Determination, and Passive hyperccmia or Passive coni^esiion. As these conditions form an essential part in all inflammatory processes, it will be convenient to consider them here ; though it must be distinctly understood that congestion is not necessarily an inflammatory condition. Any cause which retards the return of the blood through the veins—as, for instance, a ligature tied round a limb—may determine passive congestion, which is therefore a purely mechanical con- dition ; whilst active congestion is a normal process, called into action by the needs of an increased supply of blood, for temporary purposes, in a thousand of the actions of daily life, such as the afflux of blood to the salivar\ glands during mastication, the turgescence of erectile organs, and even blushing, and therefore cannot be regarded as an inflammatory process or morbid condition, though it is frequently associated with disease and forms, as we shall hereafter see, an important element in all inflammatorv processes. ACTIVE cox(;p:stion or determination Active congestion is an increased flow of blood to a part, with an increased rapidity of flow t/iroui^h the part, owing to a dilatation of the arteries and arterioles supplying it, from relaxation of their muscular coat. The blood in the part is therefore increased in quantity, flows with greater rapidity than natural, and is in consefjuence of a brighter colour than natural. If, for instance, a morsel of food is introduced into the mouth, there is at once an active congestion or determination of blood to the salivary glands ; the arteries sup[)lying the glands dilate, the blood rushes through them with increased velocity and in increased quantity, and thus, more blood being supplied to them, the functional activity of the glands is increased—there is a greater secretion of saliva for the salivation of the morsel of food. In this respect it is a perfectly normal condition and is produced by reflex action : the irritation of the sensory nerves of the mouth, induced by the food, causes immediate dilatation of the vessels supplying the salivary glands. The condition is often a very transitory one, the dilated vessels almost immetliatelv recovering their normal calibre and the blood current slowing down to its normal rate of progress. Causes.—When associated with disease, active congestion is caused by the application of some irritant, either mechanical or chemical. If, for instance, some irritant, as the prick of a needle, be applied to the web of a frog's foot, when viewed under the micro.scope, the small arterioles supplying](https://iiif.wellcomecollection.org/image/b21210846_0028.jp2/full/800%2C/0/default.jpg)
