Medical Inquiries and Observations, Vol. 3 / The Second Edition, Revised and Enlarged by the Author

by Benjamin Rush

5. There was, in every case in which the blood was not dissolved, or in which the second appearance that has been mentioned did not take place, a beautiful scarlet-coloured sediment in the bottom of the bowl, forming lines, or a large circle. It seemed to be a tendency of the blood to dissolution. This state of the blood occurred in almost all the diseases of the last two years, and in some in which there was not the least suspicion of the miasmata of the yellow fever.

6. The crassamentum generally floated in the serum, but it sometimes sunk to the bottom of the bowl. In the latter case the serum had a muddy appearance.

7. I saw but one case in which there was not a separation of the crassamentum and serum of the blood. Its colour in this case was of a deep scarlet. In the year 1793 this appearance was very common.

8. I saw one case in which the blood drawn, amounting to 14 ounces, separated partially, and was of a deep black colour. This blood was taken from Mr. Norval, a citizen of North-Carolina.

9. There was, in several instances, a transparent jelly-like pellicle which covered the crassamentum of the blood, and which was easily separated from it without altering its texture. It appeared to have no connection with the blood.

10. The blood, towards the crisis of the fever in many people, exhibited the usual forms of inflammatory crust. It was cupped in many instances.

11. After the loss of 70 or 80 ounces of blood there was an evident disproportion of the quantity of crassamentum to the serum. It was sometimes less, by one half, than in the first bleedings.

Under this head it will be proper to mention that the blood, when it happened to flow along the external part of the arm in falling into the bowl, was so warm as to excite an unpleasant sensation of heat in several patients.

To the appearances exhibited by the blood to the eye, I shall add a fact communicated to me by a German bleeder, who followed his business in the city during the prevalence of the fever in 1793. He informed me that he could distinguish a yellow fever from all other states of fever, by a peculiar smell which the blood emitted while it was flowing from a vein. From the certainty of his decision in one case which came under my notice, before a suspicion had taken place of the fever being in the city, I am disposed to believe that there is a foundation for his remark.