Pus-Formation, we have to observe, is alien to the genuine typhous process whether general or local. Wherever it does occur, it is founded in a degeneration or change in the typhus-crasis, of which we have to say a few words. No other crasis offers such manifold interest in reference to degeneration or conversion. Not alone are there several conversions of the kind, but they are remarkable for an impress the exact reverse of the original typhus. The recognition of these phases and their interpretation as degenerations or transformations, are not only of the greatest scientific interest, but also of the most obvious practical utility. These changes resolve themselves into the following. They are more or less demonstrable in the sanguineous fluid, as also more or less proclaimed in corresponding local processes.

1. Conversion to the croupous crasis.

2. Conversion to pyaemia.

3. Degeneration to acute softening [acidification of the blood].

4. Degeneration to gangrene [Sepsis, - necrosis of the blood].

1. Conversion To The Croupous Crasis

A fibrin of a constitution characteristic of the croupous crases forms in the blood. Perishable coagula [vegetations, plugging clots, so-called capillary phlebitoids] originate in the heart, in the greater vessels, in the capillaries; but, above all, exudative processes, upon mucous membranes. Those croupous inflammations of the mucous membrane lining the tracheal canal, the oesophagus, the stomach and intestines, the female sexual organs, as also croupous pneumonia, all belong to this type. Again, similar processes upon serous membranes, the yellow, fibrinous, crumbling products by which the typhous infiltrations of the mesenteric and Peyerian glands are modified.

The exudates are wont to exert a solvent influence upon their parent strata, deep corrosions of the mucous membranes beneath the exudates, more especially at the glottis and epiglottis, being not at all uncommon.

This conversion takes place at various periods of the typhous process - even at a very early stage. It is deserving of notice that a vast number of cases in point happen at the commencement of epidemics of cholera, a disease in whose typhoid [so-called reaction-] stage croupous inflammations are so frequent. [See "Exanthematous Crasis."]

The conversion of the typhus-crasis to the tuberculous - the tuberculo-croupous - crasis belongs to the same class. Its localization generally attaches to the lungs in the shape of lobular - not unfrequently of a comprehensive lobar pneumonia; - pneumonic tubercle-infiltration.

2. A Second Conversion Of The Typhus-Crasis

A Second Conversion Of The Typhus-Crasis, kindred with the preceding one, is that to pyaemia and local pus production. It occurs, for the most part, at a later period than the one just referred to, often complicating the last stage of the local typhus-process upon the mucous membrane of the ileum, and protracting itself into a sequela to the typhus. Examples hereof are the pus-deposits in the typhous patches upon the mucous membrane of the ileum, and in the infiltrated mesenteric glands; the pus-producing areolar-tissue inflammations; the purulent exudates upon serous tunics; the circumscript, suppurating coagulations in the capillary system of the lungs, the spleen, the kidneys; the boil-like obstructions of the capillaries in the substance of the mucous membranes and of the outer skin.

3. Degeneration To The Acute Softening Process

Degeneration To The Acute Softening Process, that is, to a crasis in which the latter is founded, and which is localized in softening of the stomach, etc We believe this process to be a peculiar one, quite distinct from putrid decomposition and its characteristic, gangrenous sloughings. That which concerns us here occurs as black, or Indian ink-colored softenings or meltings of the textures in an acid fluid, especially in the ccecal sac of the stomach, on the left side of the oesophagus, in the lungs, upon the mucous membrane of the ccecum, and in the urinary bladder.

"We believe this process to be derived from the blood in the capillaries of the parts referred to, and to be due to an acidification of the blood-mass, - to the presence of a free acid in the blood:

(a.) It is developed out of a hyperaemia and stasis in the implicated organs, and in point of fact, out of the blood engaged in the stasis, which experiences the first effect of the liberated acid upon itself, in the shape of inspissation and coagulation to a black, pitch-like, friable mass, destructive of the walls of the vessels and of other contiguous textures.

(b.) The reaction of the structures softened is invariably acid.

(c) Our view seems to derive support from the determination of the blood under these circumstances to the caecal sac of the stomach, which, with the spleen, appears to us to perforam the office of a de-acidifying apparatus to the blood-mass, for the immediate secretion of the gastric juice and in behalf of the hepatic function.

(d.) A very frequent appearance associated with the impending softening, is that of a miliary eruption with acid reaction of the contents of the vesicles.

4. Degeneration To Sepsis

Degeneration To Sepsis; putrid-crasis. Primary gangrene of the solids. It occurs either very early, or only as a sequel to typhus.

The blood and the dead body exhibit the peculiar changes to be described in another place.

Where the putrid character, is early developed, the faint impression in its localization, especially with respect to plasticity of its products, is remarkable. The Peyerian gland-groups are turgid with sero-albumi-nous infiltration, lax, and, together with the mucous membrane of the ileum, generally ecchymosed.

As the local manifestation of this degenerate state, sloughing takes place in parts exposed to hypostasis and pressure, for instance, in the sacral region, at the trochanters, etc. This is not all, however: hyperae-miae and stases become developed even in parts beyond the range of hypostasis, leading incontinently to mortification of the textures, - for example noma of the cheeks, sphacelus of the external sexual organs in the female.

All these degenerations may become localized in the typhus-ulcers, leading, as will be seen, in the account given [see vol. ii.] of the local typhus-process in the intestinal membrane, to a destruction overstepping the limits of the textures, and frequently to perforation of the intestine.

Other sequelae of the typhus-crasis are protracted albuminuria [Bright's disease], anaemia [with wasting], hydraemia [(Edema, Dropsy].