68 PROPERTIES OF 



ooze out in twenty-five minutes after opening the vein ; the 

 blood on the plate was later in coagulating, and none of these 

 portions of blood had the least appearance of size. But the 

 blood in the first cup was considerably, the latest in jellying ; 

 for at the end of twenty-five minutes a large quantity was still 

 fluid under the pellicle, and even at the end of fifty minutes 

 the coagulation was incomplete. This blood seemed to have 

 rather more size than that in the former experiment, but it was 

 not collected at one part, but was diffused over the surface, and 

 appeared in spots not bigger than pins' heads. 



The result, therefore, of this experiment was similar to the 

 preceding. The ligature long continued produced a size, but 

 in small quantity; and therefore it does not appear probable, 

 that, when the ligature has been only a few minutes on the arm 

 (as is the case in the ordinary manner of bleeding), it can de- 

 serve to be taken into the account, when we judge of the dis- 

 ease, or of the indications of cure from the appearance of the 

 size; especially when it is considered that the blood on which 

 these experiments were made was very favorably circumstanced 

 for Dr. Simson's opinion; that is, it was from a patient who 

 seemed to be plethoric, by the blood which was first taken away 

 not jellying in less than thirty, and thirty-four minutes, which 

 is later than ordinary, as appears from what is observed above, 

 page the 35th ; where we found, that the blood of people in 

 health commonly jellies in seven or eight minutes. 



As many of these experiments show how easily the disposi- 

 tion of the lymph to coagulate can be altered, even by slight 

 changes, as it would seem, in the state of the blood-vessels, 

 they help us to explain how it should happen, that the blood, 

 in some diseases, is found without this property of jellying ; an 

 instance of which is mentioned by M. de Senac 1 ; another 



1 Traite du Coeur, torn, ii, p. 129 (xxxm). 



(xxxm.) Senac's case 3 is as follows : " Un homme de trente-cinq ans 

 avoit une ancienne galle, je le fit saigner, son sang ne se figea point." 

 In most of the instances observed by Dr. Davy, b in which the blood 

 was liquid after death, and without the power of self-coagulation, the 

 fatal event was referrible either to drowning, hanging, the fumes of 

 charcoal fire, or effusion of blood into the bronchia or air-cells. 



A man aged 35, and his three children, aged \\, 4J, and 6^ years, 



a Ed. 1749, t. ii, p. 129. b Researches, Physiol. and Anat. ii, 192. 



