Its domain, viewed from the anatomical side is a very extensive one. However, we might wish to limit this crasis to scarlatina and measles, a number of acute blood diseases naturally cluster around them, become localized upon the greater mucous membranes, and not unfrequently, especially in epidemics, produce exanthemata presenting more or less analogy with genuine measles, or pure scarlatina. Amongst them are some which determine a more or less plastic, albumen-loaded, coagulating or colloid-like, thinly purulent, almost serous product upon mucous membranes; exudatory processes which bring the muco-membranous texture into a state of dissolution; Asiatic cholera; numerous puerperal affections; acute diarrhoea, especially in children; nay, even exanthema-tous typhus; in fine, many substantive [exanthematous] fevers without exanthema. At the uttermost limits of this domain are placed blood diseases, associated with tonic spasm and convulsions, - with affections of the nervous centres. Last of all, acute tuberculosis. In the present section, however, we shall only speak of the exanthematous crasis and of those nearest allied to it, leaving the remainder to be discussed in separate chapters. The crasis in question is the most distinctly marked in scarlatina; and it is here that we have the best opportunities for studying it in the dead body. In degree, the crasis of measles is perhaps nearly the same, as are also the blood diseases already stated to follow next in the scale.

Upon the whole, the exanthematous crasis has the greatest affinity to the typhous. Only the blood is still more fluid, whilst the violet tint present in intense typhus is wanting. The blood verges more upon purple, - upon cherry-red.

The dead body manifests a certain degree of turgor. There is a lack of that tenseness of the muscles, and of the common integument, as also of the dingy-gray coloration of the latter. The skin is indeed rather white, although with extensive, very saturated death-patches. The serous membranes very often exhibit a viscid, ropy, colorless covering. Local hy-peraemiae, partly of hypostatic nature, and imbibition of the textures with blood-pigment, are observable.

Along with these differential points, and apart from the resemblance in the anatomical characters of the blood, special analogies come forth between the typhous and the exanthematous crasis. Such as:

(a.) The relation of the exanthematous crasis to the mucous membranes, and also to the lymphatic glands. It is expressed in the well-known catarrhal, erythematous, and other affections of the respiratory and gastro-enteric tracts of mucous membrane; - in the well-known enlargements of peripherous lymphatic glands accompanying the course of the exanthemata. What is, however, particularly characteristic, is the development of the follicle apparatus of the ileum and of the mesenteric glands in scarlatina, and in the entire series of analogous blood diseases.

(b.) The identical conversions of the crasis observed in typhus. The most frequent are the conversion to the croupous crasis, including the tuberculo-croupous, with corresponding local products, and the often early degeneration to putrid decomposition.

Among the sequelae there is one proper to typhus, and also a very frequent consequence of scarlatina, - namely, protracted albuminuria.

Another consequence of the exanthematous processes, is intense inspis-sation of the blood, with marked hyperaemiae and stases.

As far as its crasial source is concerned, variola does not seem to constitute an exception. It is, however, essentially obnoxious to a speedy transition into the croupous-crasis and into pyaemia, the latter often outrunning its normal term. In common with the exanthematous crasis generally, it is liable to degenerate early into putrid decomposition, which, anticipating the croupous and the pyaemic phases, precludes the formation of any products due to these modifications of the exanthema, and causes the pocks to degenerate into the so-called putrid.

Amongst the diseases following closely in the wake of the more prominent exanthemata, the under-mentioned are peculiarly deserving of notice, namely:

A large proportion of puerperal fevers - especially when bearing an epidemic impress. The characters presented by the dead body, and the anatomical relations of the blood, answer to the exanthematous crasis; to which may be added, the presence of the exudatory processes above specified upon the uterine mucous membrane, the character of exudates detected upon the serous membranes, especially the peritoneum, and finally, the frequency of concurrent exanthema, in the shape of erythema and of scarlatina. These puerperal processes are marked by their tendency either to become converted into the croupous crasis, or else to degenerate into putrid decomposition. Nor is acute softening of the stomach a rare coincident phenomenon.