In the slighter cases the lesions are often largely confined to the anterior part of the respiratory organs. The _fauces_, _pharynx_, _larynx_, _guttural pouches_ and _nasal mucosa_ are tumified, congested, red and covered with mucous, and this condition may extend down to the bronchia. In such cases the _blood_ is normal or may coagulate with undue readiness and firmness. The pharyngeal and intermaxillary lymph glands are red and congested in their outer zone. In the more severe cases the _alterations in the blood_ are perhaps the most constant of the morbid features. The blood is fluid and incoagulable, or the clot is soft, diffluent and black, the red globules are crenated or broken up, and show little tendency to adhere in rouleaux. The escaped hæmatoidin accumulates in masses in the serum in crystalline forms, giving it a high staining power when a line is drawn with it on white paper. Fatty globules also float in the mass. The leucocytes are relatively very much encreased and the red globules diminished. Dieckerhoff found 30,000 and Trasbot 40,000 leucocytes in a cubic millimetre. The diffluence is not constant. Blood drawn in the earlier stages of the disease, coagulates with extraordinary firmness, influenced, doubtless, by the encrease of the leucocytes, the disintegration of the blood globules, and the liberation of globulins. This serves also to partially explain the early and sudden deaths from coagula in the heart and large vessels, which are occasionally met with. Such clots in the heart are often found adherent to the valvular or ventricular endocardium which at such points shows cloudy swelling, thickening, cell proliferation and even encreased vascularity and granular elevations. In advanced cases, however, the prominent features are usually acidity, blackness, and incoagulability of the blood, its resistance to oxygen, altered and broken down red globules, free coloring matter, relative encrease of white cells, and, if necropsy has been delayed, the abundance of septic microbes (cocci and bacilli). Petechiæ are abundant on the serosæ especially on the pericardium.