But there is a grade of fever, which transcends in force that which produces inflammation. It occurs frequently in hydrophobia, dysentery, colic, and, baron Humboldt lately informed me, upon the authority of Dr. Comoto, of Vera Cruz, in the yellow fever of that city, when it proves fatal in a few hours after it attacks. In vain have physicians sought to discover, by dissections, the cause of fever in those cases, when followed by death, in the parts of the body in which it was supposed, from pain and other symptoms, to be principally seated. Those parts have frequently exhibited no marks of inflammation, nor of the least deviation from a healthy state. I have ascribed this apparent absence of disease to the serous vessels being too highly excited, and thereby too much contracted, to admit the entrance of red blood into them. I wish these remarks to be remembered by the student of medicine. They have delivered me from the influence of several errors in pathology; and they are capable, if properly extended and applied, of leading to many important deductions in the practice of physic.
I shall now briefly mention the usual effects of fever, or morbid excitement in the blood-vessels, when not removed by medicine. They are,
1. Inflammation. It is produced by an effusion of red particles of blood into serous vessels, constituting what Dr. Boerhaave calls error loci. It is the second grade of fever, and, in fevers of great violence, does not take place until morbid excitement has continued for some time, or has been reduced by bleeding.
2. Secretion, or an effusion from rupture, of the serum of the blood, constituting dropsies.
3. Secretion of lymph or fibrin, forming a membrane which adheres to certain surfaces in the body.
4. Secretion of pus, also of sloughs.
5. An effusion by rupture, or a congestion of all the component parts of the blood.
6. Gangrene from the death of the blood-vessels.
7. Rupture of blood-vessels, producing hæmorrhage.